Revision of the Fire of the Solenopsis saevissima - Group (: Formicidae) Author(s): James P. Pitts, Gabriela P. Camacho, Dietrich Gotzek, Joseph V. Mchugh and Kenneth G. Ross Source: Proceedings of the Entomological Society of Washington, 120(2):308-411. Published By: Entomological Society of Washington URL: http://www.bioone.org/doi/full/10.4289/0013-8797.120.2.308

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REVISION OF THE FIRE ANTS OF THE SOLENOPSIS SAEVISSIMA SPECIES–GROUP (HYMENOPTERA: FORMICIDAE) urn:lsid:zoobank.org:pub:F387D696-11D6-4649-A9BC-82D8344F0764

JAMES P. P ITTS,GABRIELA P. C AMACHO,DIETRICH GOTZEK,JOSEPH V. M CHUGH, AND KENNETH G. ROSS

(JPP) Department of Biology, Utah State University, UT 84326 USA (e-mail: james. [email protected]); Department of Entomology, University of Georgia, Athens, GA 30602 USA; (GPC) Programa de Po´s-Graduac¸a˜oemEntomologia,DepartamentodeZoologia, Universidade Federal do Parana´,Curitiba,Parana´ 81531-990 (e-mail: gabieco. [email protected]); Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013 USA; (DG) Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013 USA (e-mail: [email protected]); (JVM) Department of Entomology, University of Georgia, Athens, GA 30602 USA (e-mail: [email protected]); and (KGR) Department of Entomology, University of Georgia, Athens, GA 30602 USA (corresponding author, e-mail: [email protected])

urn:lsid:zoobank.org:author:89B4EC38-0687-4650-9F0E-AF2324459E10 urn:lsid:zoobank.org:author:9E0ECF1A-5F0F-496B-865B-33EBCF9721A7 urn:lsid:zoobank.org:author:AAD26B8C-D864-4CAD-AB19-ED2637179F58 urn:lsid:zoobank.org:author:9CA20153-0D9B-4839-A3EA-B02AC2F5CBB3 urn:lsid:zoobank.org:author:58B33294-7A7A-4012-BCE0-9AEFAAB3B0F8

Abstract.—The fire ants of the Solenopsis geminata species-group of Trager (1991) are revised based on the morphology of worker larvae and of adult forms of workers, males, and gynes (winged or dealated members of the queen caste). The amount of intraspecific variation occurring in the adult males and gynes was equivalent to that of workers, making the taxonomic information gained from these castes no better than information from the workers. A new species, S. metallica,isdescribedfromsouthernBrazil,basedonadult workers, adult gynes, males, and worker larvae. The following classification changes are made: S. virulens is placed in the S. virulens species-group; S. tridens and S. substituta are placed in the S. tridens species-group; S. metallica new species, S. daguerrei, S. electra, S. hostilis, S. interrupta, S. invicta, S. macdonaghi, S. megergates, S. pusillignis, S. pythia, S. quinquecuspis, S. richteri, S. saevissima, and S. weyrauchi are placed in the S. saevissima species-group; and S. geminata, S. xyloni, S. amblychila, S. aurea, S. gayi, and S. bruesi are left in the S. geminata species-group. The older classification, which designated complexes and subcomplexes, is abandoned. For the S. saevissima species-group, adults of males and gynes, as well as worker larvae, are describedanddiagnosedforeachspecies.Diagnoses and keys (dichotomous and tabular) are provided for adult workers, the most commonly collected material, and distributions of the species are summarized. VOLUME 120, NUMBER 2 309

Key Words: fire ants, red imported fire , black imported fire ant, Solenopsis geminata species-group, , DOI: 10.4289/0013-8797.120.2.308

Fire ants are placed in the Sol- been introduced throughout the tropics enopsis Westwood (Hymenoptera: For- worldwide (Wetterer 2011, Gotzek et al. micidae) in the subfamily Myrmicinae. 2015), S. invicta has been introduced to There are approximately 190 described the and several other Pacific species of Solenopsis worldwide (Bolton Rim countries (Lofgren 1986, Callcott 1995). Most of these species are charac- and Collins 1996, Henshaw et al. 2005, terized by small, monomorphic workers Ascunce et al. 2011, Wetterer 2013), and that form small colonies and can display S. richteri has been introduced to the a lestobiotic lifestyle, living in the nest United States (Lofgren 1986). walls of other ant species from which Solenopsis invicta and S. richteri have they steal food and brood (Thompson become economically important pests in 1980, 1989; Pacheco and Mackay 2013). the United States, where they invade These habits have earned such Solenopsis lawns, pastures, and roadsides, attacking species the name “thief ants.” A smaller and stinging native , livestock, group composed of five species of and humans when colonies are dis- Solenopsis are considered inquiline social turbed, and evidently out-competing parasites of other ant species. These in- native ants for food and nesting quiline social parasites live alongside the (Lofgren et al. 1975, Jouvenaz 1990, host queen, generally lack a worker caste, Guillebeau et al. 2002, Tschinkel 2006). and their brood is made up only of sex- Annual economic losses in the United uals (Buschinger 2009). Among the re- States attributable to the imported fire maining Solenopsis are 20 New World ants are estimated at $6 billion (Lard species that differ greatly from the thief et al. 2006). Although the pugnacious ants and social parasites in their biology. nature of these exotic ants makes them These species have larger, polymorphic undesirable inhabitants of areas that they workers, form enormously populous col- have newly colonized, they nonetheless onies, and are highly aggressive in their have become premier objects of study foraging and defensive habits. The pain- for ecologists and evolutionary bi- ful sting wielded by the workers has ologists. For instance, fire ants offer one earned such Solenopsis species the name of relatively few well-documented cases “fire ants.” Most fire ant species are of the formation of a hybrid zone in Neotropical, although five species are historical times (Vander Meer et al. native to North America (Chialvo et al. 1985, Ross et al. 1987a, Shoemaker et al. 2018). One of these (Solenopsis geminata 1996), which makes them a rich source (Fabricius), the tropical fire ant) and two of information for genetic studies of of the Neotropical species (S. invicta speciation (Baack and Rieseberg 2007, Buren, the red imported fire ant, and Nolte and Tautz 2010). Fire ants also Solenopsis richteri Forel, the black im- show variation in the social organization ported fire ant) have been inadvertently of their colonies, some of which appears introduced to locations far from their to be under simple genetic control native ranges. Solenopsis geminata has (Krieger and Ross 2002, Wang et al. 310 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

2013), making them important model apparently believed that the South Ameri- systems in the study of social evolution can fire ants comprise nothing more than (Gotzek and Ross 2007, Smith et al. 2008, alargehybridswarmofunstablevariants. Robinson et al. 2008, Fischman et al. 2011). Further complicating matters is the fact The flexibility demonstrated by some species that several of the species in North Amer- in having either a single egg-laying gyne ica (both native and introduced) hybridize (monogyny) or multiple egg-laying gynes extensively where their ranges overlap () in a single colony has sparked (Shoemaker et al. 1996, Helms Cahan and comparative ecological and evolutionary Vinson 2003, Ross and Shoemaker 2005). studies about the causes and consequences Although the fire ants as a group have of such variation (Vargo and Fletcher 1987, been revised fairly recently (Trager 1991), Ross and Keller 1995, Porter et al. 1997, some unresolved taxonomic problems re- Gotzek and Ross 2007, Huang and Wang main. Thus, we undertook a systematic 2014). Solenopsis also includes several so- study with several specific objectives in cial parasites that use various ant species as mind. The first was to develop additional their hosts (Calcaterra et al. 2000, Davis morphological character systems to aid in and Deyrup 2006, Deyrup and Prusak the definition and identification of fire ant 2008), a characteristic that is of great in- species by evaluating life stages and castes terest for studies of social evolution as well other than adult workers. Data from the as integrated pest management. It is re- diverse morphological character systems markable that in spite of the extensive re- developed for this study also were used to search conducted on fire ants, no thorough produce a phylogenetic hypothesis for the taxonomic treatment or phylogenetic anal- S. saevissima species-group (Pitts et al. ysis of the group has been conducted. Only 2005). The second objective was to revise three phylogenetic analyses have been the classification of the fire ants fol- published, one based on morphology (Pitts lowing cladistic methodology, whereby et al. 2005), another using mitochondrial only monophyletic groups are designated DNA (Shoemaker et al. 2006), and the third (sensu Pitts et al. 2005). based on nuclear allozyme markers (Ross We acknowledge the limitations of a and Trager 1990). All suffer from limited purely morphological approach in such taxon and/or character sampling and the acomplexandintractablegroup.Itisevi- appearance of poorly supported clades. dent that our current morphological analyses Historically, Solenopsis has been a tax- capture only part of the (genetically) di- onomically difficult group (Creighton agnosable diversity of the group (Ross and 1930, 1950; Wilson 1952; Buren 1972; Trager 1990; Ross et al. 2007, 2010), and Trager 1991; Pacheco and Mackay 2013). thus our results almost certainly represent In , where species diversity alowerlimittotheactualnumberofspecies. is highest, distinguishing Solenopsis spe- However, taxonomically and geographically cies is exceedingly difficult due to a pau- restricted genetic approaches, while un- city of reliable characters that are constant covering cryptic diversity within a few within putative species yet differ between nominal species (nominal S. richteri, S. in- them. Frustration with this situation victa,andS. saevissima), have confirmed the prompted Carlo Emery to call the group distinctiveness of the current morphologi- the crux myrmecologorum (Creighton cally recognized species (Ross and Trager 1930) and led Wilson (1952) to propose 1990; Ross et al. 2007, 2010; Shoemaker several synonymies, reducing the number et al. 2006). We caution against the over- of fire ant species to only three. Wilson interpretation of single locus datasets VOLUME 120, NUMBER 2 311

(Shoemaker et al. 2006,Gotzeketal.2007), “satellite” genera Lilidris Kusnezov 1958, which can be construedtosuggestthatsome Bisolenopsis Kusnezov 1953,Labauchena morphologically diagnosed species are not Santschi 1930, and Paranamyrma monophyletic and hence not “real” entities. Kusnezov 1953 under Solenopsis, but Instead, we suggest using the multi-species gave little explanation for this decision. coalescent accommodating incomplete lin- He recognized three “natural” groups in eage sorting and hybridization (Fujita et al. Solenopsis: the fire ants, the social para- 2012) as a better model to understand ge- sites, and the thief ants. The fire ants netic patterns in fire ants. We consider our comprised species previously placed in morphological species concept a necessary, the subgenus Solenopsis, the social par- important, and invaluably practical first step asites were species from the genera to continued systematic efforts, which will Labauchena and Paranamyrma, and the ultimately require iterative and highly in- thief ants were species of all the other tegrative taxonomic approaches and datasets synonymized genera and subgenera. to be utilized to test, refine, and correct our Some higher-level taxonomic work has current morphological understanding of been done on Solenopsis since Ettershank. species limits in fire ants. Baroni-Urbani (1968) resurrected the Taxonomic history of Solenopsis.— subgenus Diplorhoptrum and elevated it to Westwood described the genus Solenopsis the generic level, placing all thief ants in in 1840 for the type species,S.geminata. this genus. He based his decision on the Creighton (1930) revised the genus and di- genitalia of the common European spe- vided it into five subgenera, Diagyne Sant- cies, S. fugax (Latreille), without knowl- schi,DiplorhoptrumMayr,Euophthalma edge of the New World thief ant fauna. Creighton,OedaleocerusCreighton, and Bolton (1987) presented arguments re- Solenopsis.ThesubgenusSolenopsis in- futing Baroni-Urbani’s decision as well as cluded the typical polymorphic fire ants, supporting Ettershank’s (1966) other syn- with the other four subgenera considered onymies, and again made Diplorhoptrum the thief ants. Creighton’s revision included ajuniorsynonymofSolenopsis. all Solenopsis species except for those in the The thief ants in Diplorhoptrum were subgenus Diplorhoptrum,whichisalarge separated into five species-groups by portion of the genus and, to date, these Creighton (1930). This system was species have not been revised. Creighton abandoned shortly afterward due to based the delineation between the thief ant various shortcomings. For instance, the subgenera mostly on morphology of the relationships of the species-groups were gynes. Unfortunately, gynes were unavail- never resolved, and many recognized able for many of the species included in his species were never placed in one of study and many remain unknown. There Creighton’s species-groups. The most also are cases where the gynes differ sub- serious problem, however, was that stantially between certain species but the subspecies sometimes were classified in workers of these same species do not, and different species-groups than their con- social parasitism cannot be ruled out. In specifics. More recently, Trager (1991) light of these problems, it is undesirable to placed all species of the old subgenus have a subgeneric classification that is based Diplorhoptrum in a single, informal primarily on the gyne caste. species-group called the S. fugax group, Ettershank (1966) realized these prob- but the justification for this change was lems and synonymized the five sub- unclear. He also discussed a S. tenuis genera. He also synonymized the related subcomplex, which presumably belongs 312 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON in the S. fugax group, however, he did S. succinea sp. com. within the newly not specify which taxa belonged in the erected S. wasmanni sp. com., further new subcomplex. Based on Trager’s recognized a S. stricta sp. com., and discussion of these new groups, one can renamed the S. azteca and S. minu- only surmise that the S. fugax group tissima sp. com. as the S. brevicornis was to contain other subcomplexes as and S. pygmaea sp. com., respectively. well. Pacheco and Mackay further synony- Moreno-Gonzalez (2001) treated the mized Carebarella with Solenopsis, North American species of Diplorhop- which was subsequently supported by trum and suggested many species-group molecular phylogenetic analyses (Ward changes. She resurrected Creighton’s et al. 2015). S. azteca (sp. com.), Compared to the New World, the Old and rearranged his remaining species World Solenopsis fauna has received complexes by placing the S. laeviceps much less attention. Galkowski et al. and S. basalis-tenuis species complexes (2010) recognized four ‘morphological’ in the S. molesta sp. com. She placed groups in France: the S. fugax, S. debil- Creighton’s S. westwoodi sp. com. in the ior, S. lusitanica, and S. orbula groups. It S. fugax sp. com. of Trager. However, as is not clear whether their concept of the discussed above, Trager’s S. fugax S. fugax complex matches that of Pa- sp. com. presumably already contained checo and Mackay (2013) and Moreno- all thief ants, so we must assume that she Gonzalez (2001) because the works do intended to place this group in the not reference each other. However, some S. fugax subcomplex, which was left concordance is expected given that Pacheco undefined by Trager. Moreno-Gonzalez and Mackay explicitly state a morpho- (2001) also erected a new species com- logical similarity between members of the plex for S. succinea—previously the sole New World S. fugax species complex and member of the subgenus Diagyne— the Holarctic species S. fugax. called the S. succinea sp. com. and Recent molecular phylogenetic ana- erected the S. minutissima sp. com. to lyses confirm the placement of Sol- contain several species, described and enopsis in the tribe Solenopsidini, its undescribed, that were not treated by senior synonymy status with Care- Creighton. She suggested that the spe- barella, and identify its sister clade to be cies previously placed in Euophthalma composed of Tropidomyrmex and Kemp- should be split into two groups, the S. fidris (Ward et al. 2015), thus disproving globularia sp. com. and the S. nigella sp. previous earlier hypotheses aligning it com., based on morphology of the with Oxyepoecus Santschi (Ettershank postpetiole. 1966, Bolton 1987). More recently, building on Moreno- The fire ants have been treated taxo- Gonzalez’ work, Pacheco and Mackay nomically several times (e.g., Creighton (2013) recognized eight species com- 1930, Wilson 1952, Buren 1972). In the plexes in their monographic revision of latest revision, Trager (1991) grouped all New World Solenopsis (excluding the of the fire ant species in the Solenopsis fire ants). While they retained Moreno- geminata species-group. Trager con- Gonzalez’ S. fugax, S. nigella, and S. firmed that all satellite genera, except globularia sp. com., they expanded her Lilidris, were synonymous with Sol- S. molesta sp. com. to include Creighton’s enopsis, reaffirming Ettershank’s syn- subgenus Oedaleocerus,subsumedthe onymies. His treatment differed from VOLUME 120, NUMBER 2 313

Ettershank’s in proposing two indepen- Solenopsis daguerrei, S. solenopsidis dent derivations of social parasitism and, perhaps, S. hostilis exhibit perma- (in the former genera Labauchena and nent social parasitism. Solenopsis da- Paranamyrma) rather than a single ori- guerrei has been reported to kill the host gin within Solenopsis. Trager’s revision queen in laboratory studies (temporary included the four North American spe- social parasitism; Bruch 1930), but has cies, two hybrids, and 17 species from been found to allow the host queen to South America, three of which were live in field studies (permanent social described as new. One of these species, parasitism; Silveira-Guido et al. 1965). S. virulens, Trager considered not a true It may be that under certain conditions S. member of the fire ants, which would daguerrei exhibit either form of social render his S. geminata species-group parasitism. This species is known to be paraphyletic. This species was also no- a social parasite of Solenopsis invicta, S. tably ignored by Moreno-Gonzalez richteri, S. macdonaghi, and S. quin- (2001) and Pacheco and Mackay (2013). quecuspis (Santschi 1930, Briano et al. The species that Trager recognized were 1997, Calcaterra et al. 2000). Borgmeier distinctive both morphologically and (1959) reported S. hostilis as a parasite genetically (Ross and Trager 1990), but of S. saevissima (Smith), but did not several studies using genetic data have gather any natural history information further complicated the problematic for the species. Solenopsis solenopsidis is alpha- of fire ants by suggest- reported to be a permanent social parasite ing the presence of cryptic species (Ross of S. clytemnestra Emery (Kusnezov and Shoemaker 2005; Ross and Trager 1954). Ho¨lldobler and Wilson (1990) re- 1990; Ross et al. 2007, 2010; Chialvo viewed social parasitism and included the et al. 2018). known parasites and hosts of the Sol- The Solenopsis social parasites.— enopsis social parasites. However, the Because Labauchena and Paranamyrma host records they listed often disagreed were synonymized under Solenopsis with those of the primary publications (Ettershank 1966), Solenopsis now in- (Bruch 1930; Santschi 1930; Borgmeier cludes several species of social parasites. 1949, 1959; Kusnezov 1954, 1957; Silveira- Two of these, S. daguerrei Santschi Guido et al. 1965). Solenopsis enigmatica and S. hostilis Borgmeier, parasitize fire is known from only a single collection ants, whereas S. solenopsidis Kusnezov from dentata Mayr and is hy- parasitizes thief ants (formerly Para- pothesized to be a temporary social par- namyrma; Santschi 1930, Kusnezov asite (Deyrup and Prusak 2008). 1954, Borgmeier 1959), and S. phoretica Davis and Deyrup and S. enigmatica MATERIALS AND METHODS Deyrup and Prusak parasitize Pheidole Loaning institutions and depositories Westwood. The social parasites lead of specimens.—Specimens used in this an especially interesting life style when study were either borrowed from col- compared to other Solenopsis species, lections at the following institutions or because the parasitic gyne enters a het- have been deposited in them: erospecific colony and usurps the re- productive role of the host queen, rather AEIC – American Entomological Institute, than initiating her own colony or joining Logan, Utah, USA. a conspecific one (as in the case of AMNH – American Museum of Natural polygyne fire ants). History, New York, USA. 314 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

BMNH – The Natural History Museum, species. Furthermore, it was necessary London, United Kingdom. to have all relevant castes and life stages CNCI – Canadian National Collections, available for study of novel character Ottawa, Canada. systems, and these specimens needed to DZUP – Colec¸a˜oEntomolo´gica Padre Jesus be associated with adult workers from Santiago Moure, Curitiba, PR, Brazil. the same colony. Unfortunately, such EMUS – Entomological Museum, De- material is not readily available from partment of Biology, Utah State University, museums. Therefore, extensive sam- Logan, Utah, USA. pling was conducted in South America FSCA – Florida State Collection of Arthro- during trips made by KGR and others in pods, Gainesville, Florida, USA. 1988, 1992, and 1998, by KGR and JPP ICIB – Museu de Entomologia, Instituto de in 2001, and by DG and GPC in 2015. Biologia, FEIS/UNESP, Ilha Solteira, Sa˜o These efforts produced new specimens Paulo, Brazil. from more than 1,500 colonies. IMLA – Fundacion e Instituto Miguel Lillo, Other new material that was utilized Tucuma´n, Argentina. for this study includes 118 colonies JPPC – J. P. Pitts Personal Collection, sampled in South America in 1991 by Millville, Utah, USA. Sanford D. Porter (SDPC). This material LACM – Los Angeles County Museum of provided adult workers and some alate Natural History, Los Angeles, California, (winged) gynes for study. The alcohol USA. collection at the FSCA held samples of MACN – Museo Argentino de Ciencias Nat- undetermined South American Solenopsis urales, Buenos Aires, Argentina. from more than 1,500 colonies that were MCZ – Museum of Comparative Zoology, collected primarily by William F. Buren. Cambridge, Massachusetts, USA. Material from the 1988 and 1992 col- MHNG – Muse´um d’Histoire Naturelle, lecting trips made by KGR was identified Geneva, Switzerland. by James C. Trager and from the 2015 MZSP – Museu de Zoologia, Universidade de collecting trip was identified by DG and Sa˜o Paulo, Sa˜o Paulo, Brazil. GPC. All other material in the study was NHMB – Naturhistorisches Museum, Basel, identified by JPP. Switzerland. Material examined.—Although the SDPC – Sanford D. Porter Personal Collec- main focus of this study is the S. sae- tion, Gainesville, Florida, USA. vissima species-group, specimens of many UCDC – University of California, Davis, other Solenopsis species were studied in California, USA. order to give insight into the usual levels of UGCA – University of Georgia Collection of interspecific variation within the genus and , Athens, Georgia, USA. to indicate other possible characters of USNM – National Museum of Natural His- taxonomic importance in the S. saevissima tory, Washington, D.C., USA. species-group. Listed alphabetically below are all species examined for this study. Sample collection.—Due to the taxo- Four forms of each species (adult males, nomic difficulties with the S. saevissima adult gynes [winged or dealated members species-group, it was deemed important to of the queen caste], adult workers, and obtain specimens from localities through- larval workers) were studied unless other- out each species’ known range in order wise indicated: S. abdita Thompson, S. to infer the extent of geographically- amblychila Wheeler (adults, all castes), based variation in character states within S. aurea Wheeler (adults, all castes),S.bruesi VOLUME 120, NUMBER 2 315

Creighton (adult workers), S. carolinensis acetate and allowed to slowly air-dry in (Forel) (adult gynes and workers), S. castor a fume hood. This technique prevented Forel (adult workers), S. clytemnestra fragile specimens from collapsing and Emery (adult workers), S. corticalis Forel also helped to maintain their natural color. (adult gynes and workers), S. daguerrei Morphological terminology and Santschi (adult males and gynes),S.elec- measurements for adults.—Several fea- tra Forel (adult gynes and workers), S. fu- tures of the head were used in this study. gax (Lat.) (adults, all castes), S. gayi The positions of the compound eyes (ce) (Spinola) (adults, all castes), S. geminata and ocelli (oc) are important and are (Fabricius), S. globularia littoralis (Smith), labeled in Figs. 1, 4, 9, and 10. The S. interrupta Santschi,S.invictaBuren,S. apices of the clypeal carinae (cc) (Fig. 1) krockowi Wheeler, S. macdonaghi Sant- are called clypeal teeth. Sometimes schi,S.megergatesTrager,S.molesta paracarinal teeth are present lateral to (Say), S. nigella Emery, S. pergandei Forel clypeal teeth, as is a small median tooth (adults, all castes), S. picta Emery, S. pu- (mct) between the clypeal teeth (Fig. 1). sillignis Trager, S. pythia Santschi (adult Often a linear or triangular shaped, darkly gynes and workers), S. quinquecuspis pigmented area, called a median frontal Forel,S.richteriForel,S.saevissima streak (fs = frontal median streak), is present (Smith),S.substitutaSantschi, S. succinea on the head (Fig. 50). Emery (adult gynes and workers), The mesosoma of the worker is di- S. tennesseensis Smith (adult males and vided into several well-defined regions. workers), S. tenuis Mayr (adult Visible in dorsal view are the pronotum workers), S. texana Emery (adult and (prn), mesonotum (mes), metanotum larval workers), S. tonsa Thompson (met), and the propodeum (ppm) (Fig. 2). (adult workers), S. tridens Forel, S. virulens In lateral view, the profiles of these, as (adult workers), S. westwoodi Forel well as the mesopleura (msp), are visible (adults, all castes), S. weyrauchi Trager (Fig. 3). The mesosoma of males and (adult workers), and S. xyloni McCook. gynes is divided into additional sclerites. Specimen preparation.—For scanning The following are usually visible: pro- electron micrographs, the adults and notum (prn), mesonotum (mes), para- larvae were dehydrated in ethanol and psidal lines (pl), scutellum (sct), axillae critical point-dried before being sput- (ax), metanotum (met) and propodeum ter-coated with gold. Several attempts (ppm) (Figs. 2, 5, 9). The mesopleuron is were made to prepare specimens using divided into a dorsal sclerite, the anepis- hexamethyldisilazane (HMDS), as de- ternum (an), and a ventral sclerite, the scribed by Nation (1983), but because katepisternum (k) (Figs. 5, 9). The wing this approach often caused damage to venation terminology used here (see Fig. 11) adult male and larval specimens it was is based on the system proposed by discontinued. Comstock (1918), Ross (1936), and For stereoscopic light microscopy, Mason (1986). workers were air-dried after storage in The metasoma has a two-segmented 70%-85% ethanol. Air-drying speci- petiole. These two segments are referred mens, especially males, directly from an to as the petiole (pt) and the post- alcohol solution often causes the head petiole (ppt) (Figs. 5, 9). The dorsal and mesosoma to collapse, resulting in surface of each of the segments is modi- low quality specimens. Therefore, males fied as an upwardly directed scale or as and gynes were saturated with amyl a rounded node when viewed laterally. 316 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

The remaining portion of the metasoma, drawn through the lateral ocelli, with the gaster, is comprised of four segments, the head in full-face, dorsal view each bearing a dorsal plate (tergite) and (Fig. 6). ventral plate (sternite). The tergites and HL Midline length of head, measured in sternites covering these segments are full-face, dorsal view, from the an- numbered from anterior to posterior as terior clypeal margin to the midpoint T1, T2, T3, T4, and S1, S2, S3, and S4, of a line drawn across the occipital respectively. margin (Fig. 6). The male genitalia are composed of EL Maximum length of compound eye, several structures. The outermost struc- measured with the head in full-face, tures are the parameres. Mesad of the dorsal view (Fig. 6). parameres are the volsellae (Fig. 74). OD Ocellar distance, measured as the Each volsella has a single cuspis (cus) distance from the middle of the me- and digitus (dig) (Fig. 74). The in- dian ocellus to the midpoint of a line nermost organ is the aedeagus, which drawn between the lateral ocelli. has an apodeme (ap) projecting dorsally Measured with the head in full-face, (Fig. 74) (Snodgrass 1941). dorsal view (Fig. 6). Measurements of adult Solenopsis OOD Ocellocular distance, measured as were made at 50X or 100X on a stereo the distance from the middle of the dissecting microscope with either an median ocellus to a line drawn across ocular micrometer or a digital microm- the posterior margins of the com- eter. All measurements are reported in pound eyes (this distance is negative millimeters. Measurements of holotypes in value if the posterior margin of the are listed separately in parentheses. compound eye exceeds the median Head measurements were made with the ocellus) (Fig. 6). head held in dorsal view, positioned so LOW Maximum width of the lateral ocelli. that the greatest straight-line distance MOW Maximum width of the median between the midpoints of the clypeal ocellus (Fig. 6). border and the vertex was achieved. The CD Distance from the anterior clypeal viewing axis was approximately per- margin to a line drawn across the pendicular to the surface of the frons. anterior margins of the frontal cari- Abbreviations and definitions for mea- nae (Fig. 6). surements and indices are given below: MFC Minimum distance between the frontal carinae, measured with the L Total length of the ant, measured in head in full-face, dorsal view. lateral view with the head in a natural EW Maximum width of compound eye, hypognathous position. This mea- measured along its short axis, in an surement is not as accurate as the oblique dorsolateral view of the head. DML measurement (below) due to SL Length of scape, excluding the radicle distortion of the metasoma that is (Fig. 6). caused by alcohol preservation and SW Maximum width of the scape, mea- subsequent drying of specimens. sured only for males. HW Maximum width of the head, in- PDL Maximum exposed length of the cluding the eyes, measured in full- pedicel, excluding the concealed face, dorsal view (Fig. 6). basal articulating area. VW Width of the posterior portion of the PEW Maximum width of the pedicel, head (vertex), measured along a line measured only for males. VOLUME 120, NUMBER 2 317

LFl Maximum exposed length of the PPW Maximum width of the postpetiole, first flagellomere. measured in dorsal view. LF2 Maximum exposed length of the PHB Height of postpetiole, as measured second flagellomere. from attachment of postpetiole to T1. LF3 Maximum exposed length of the third flagellomere. Indices calculated from the preceding mea- WF1 Maximum width of the first surements include the following ratios: flagellomere. FL Maximum exposedlengthofthefore CI Cephalic index: HW/HL femur, measured in posterior view. OI Ocular index: EW/EL FW Maximum measurable width of the REL Relative eye length: EL/HL fore femur, measured from the REL2 Relative eye length, using HW: EL/ same view as FL, at right angles to HW the line of measurement of FL. OOI Ocellocular index: OOD/OD PW Maximum width of the pronotum VI Vertex width index: VW/HW in dorsal view, measured only for FCI Frontal carinal index: MFC/HW the major workers. CDI Clypeal distance index: CD/HL MW Width of the mesonotum in dorsal SI Scape index: SL/HW view, anterior to tegulae. SI2 Scape index, using EL: SL/EL DML Diagonal length of the mesosoma, SI3 Scape index, using LF2: SL/LF2 measured in lateral view along a di- FI Fore femur index: FW/ FL agonal line drawn from the ante- NI Petiole node index: PND/PL rior base of pronotum (exclusive of PLI Petiole length index: PH/PL anterior "cervical flange" which is PHI Petiole height index, using PPL: PH/ often concealed) to posterior edge PPL of metapleuron (Fig. 7). PWI Petiole width index: DPW/PL PL Petiole length, measured in lateral PPWI Postpetiole width index: PPW/PPL view from the lateral flanges of the PPWB Postpetiole width index, using anterior peduncle to the posterior PHB: PPW/PHB margin of the petiole (Fig. 8). PND Petiolar node distance, distance The measurements for workers reported from the anterior margin of petiole here differ from those of Trager (1991) as to a vertical line drawn through the follows: the abbreviation DML is used in- petiole at the highest point of the stead of AL to denote diagonal length of node, measured from the same the mesosoma, REL is used instead of OI view as PL (Fig. 8). for relative eye length, and CI, SI, and REL PH Maximum height of the petiole, are not converted to percentages. Mea- measured in lateral view at right an- surements of head length reported here gles to PL, but excluding the ante- include the length of the clypeal teeth. roventral process (Fig. 8). Morphological terminology and PPL Length of the postpetiole, measured measurements for larvae—Only fourth in lateral view, from the anterior instar worker larvae or prepupae were used peduncle of the postpetiole to the for the study. The fourth instar is discern- point of contact with the fourth ab- ible by the completely sclerotized mandi- dominal tergite. bles (Petralia and Vinson 1979). Larvae DPW Maximum width of the petiole, were prepared as outlined in Wheeler measured in dorsal view. (1960). The morphological terminology 318 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON follows that of Wheeler and Wheeler angles distinctly defined, occiput flat (1976) (Fig. 12), however, several rows of with narrow, shallow median impres- setae also were named as follows: occipital sion. Occipital furrow clearly to weakly setal row (= posterior row of setae on head) defined. Frontal furrow indistinct. (Fig. 13), first setal row of the vertex Clypeus projecting, carinal teeth very (Fig. 14), and second setal row of the stout and acute, clypeus with anterior vertex (Fig. 15). Measurements were made shallow concave impression between at 400X or 1000X on a compound micro- carinal teeth (Fig. 1). Paracarinal teeth scope. Length was measured using the spi- small (Fig. 20), often poorly defined and, racles as in Wheeler and Wheeler (1976). in some cases, absent (Fig. 1). Median Standard taxonomic descriptions are carinal tooth well developed (Fig. 1) to provided for adult males, adult gynes indistinct (Fig. 20). Mandibles with and larval workers in the S. saevissima outer border convex, masticatory border species-group. A standard dichotomous with four teeth, fourth tooth much key is provided that incorporates useful smaller than others (Fig. 1). Eyes large, characters from adult males and gynes. strongly convex, ovate (Figs. 1, 4). An- A tabular key is also provided. tennal scape in repose reaches or passes lateral ocellus. with 11 seg- RESULTS ments (10 segments sometimes in S. Solenopsis saevissima species- pythia) with 2-segmented club. group.—Diagnoses for the gynes, males, Mesosoma: Robust, elliptical, only and larvae of the non-parasitic species of slightly narrower than head (Fig. 2). In the S. saevissima species-group are lateral view, mesonotum with convex given below. Due to the drastic modifi- anterior portion that overhangs pronotum cation in body form in the social para- and with straight posterior half (Fig. 5). sites, descriptions of each species are not Scutellum as high or higher than mes- provided here. Instead, the description onotum, slightly convex with short per- of S. daguerrei serves to distinguish pendicular posterior face, posterior all socially parasitic species from the face depressed posteromedially (Fig. 5). remainder of the species-group.Sol- Angle of propodeum well defined but enopsis hostilis has been included in the obtuse, basal face shorter than declivous key for completeness, although no face (Fig. 5). Mesosternum large and specimens were found during this study subglobose ventrally (Fig. 5). Wings hy- and the species apparently has not been aline with yellow to brown veins (veins collected since its original description. hyaline in S. daguerrei and sometimes in To avoid repeating the descriptive S. electra). treatment of the workers by Trager Metasoma: In lateral view, petiolar (1991), only diagnostic combinations node obtusely triangulate, profile of pe- of characters for the major workers are duncle flattened anteriorly, convex pos- given here. teriorly (Fig. 5). Petiole with median Gyne.—Head: Usually broader than longitudinal carina on anterior 0.50–0.75 long, quadrate, wider posterior to eyes of ventral surface (Fig. 5). Postpetiole than anterior to them, sides weakly evenly convex (Fig. 5). Lateral faces of convex from eyes to occipital angles, postpetiole concave to slightly convex. straight to slightly convex ventral to Petiolar and postpetiolar spiracles are eyes and meeting anterior border of tuberculate in some cases. Petiole with head at a sharp angle (Fig. 1). Occipital basal transverse carina, appears tooth-like VOLUME 120, NUMBER 2 319 in lateral view. In dorsal view, nodes are (Fig. 9). In cephalic view, dorsum of very strongly transverse, and post- node with shallow median impression, petiole wider than petiole. In cephalic sometimes bilobate. Postpetiole in lat- view, petiole sometimes with distinct eral view as high as node of petiole, median lobe, postpetiole broader than anterior face, dorsum and posterior face high, highest medially. rounded (Fig. 9). In dorsal view, both Male.—Head: Trapezoidal, maxi- nodes very transverse, postpetiole is mum head width greater than length approximately 1.0–3.0X as broad as long (Fig. 10). Eyes very large, strongly and as wide as node of petiole. Petiolar convex, ovate, occupying more than and postpetiolar spiracles distinctly tu- 0.5X side of head, their anterior border berculate to not tuberculate. Genitalia almost reaching insertion of mandible strongly retracted (Fig. 74). Cuspis lat- (Fig. 10). Eyes normally with setae erally flattened, lobate in lateral view protruding from between ommatidia. and lacking setae (Fig. 74). Digitus short Ocelli small to large and prominent, el- and cylindrical, with apical setae and liptical (Fig. 10), lateral ocelli marking sometimes with lateral setae (Fig. 74). boundary of occiput with shallow con- Ventral portion of volsellar plate apically cave depression between them. Anterior produced, clothed with several setae edge of clypeus approximately straight (Fig. 74). Ventral surface minutely den- (Fig. 10). Clypeus with blunt, central tate with rows of triangular teeth (Fig. lobe in lateral view (Fig. 9). Mandibles 74). Ventral margin of aedeagus with small, straight, tridentate, third tooth many anteriorly directed triangular teeth small, sometimes indistinct. Antennal (Fig. 74). Aedeagus with anteroventrally scape longer than broad, roughly cylin- directed triangular projection (Fig. 74). drical. Pedicel subglobose, broad or Apodeme of aedeagus directed perpen- broader than scape or flagellomeres (Fig. dicular to slightly obtuse to ventral sur- 10). First flagellomere >2.0X as long as face (Fig. 74). broad, second flagellomere <1.6X as Sculpture and Pilosity: Punctures fine long as broad, remaining flagellomeres and numerous, < 0.001mm wide. An- progressively decreasing in width. tenna covered with dense, short, white Mesosoma: Robust, elliptical, width pubescence. Pubescence on legs shorter less than twice that of head. In lateral and stouter than on body. view, anterior part of mesonotum greatly Fourth instar worker larva.—Head: swollen and overhanging pronotum (Fig. Antenna with 2–3 sensilla, each bearing 9). Propodeum rounded, declivous face spinule (Fig. 12). Head setae sparse (Fig. perpendicular and flat except with dis- 12). Cranial width equal to or slightly tinct to indistinct median longitudinal broader than long (Fig. 12). Labrum depression (Fig. 9), basal face strongly small, short, slightly narrowed medially convex transversely and longitudinally. (Fig. 12). Mandible heavily sclerotized Mesosternum large and subglobose with two parts (Fig. 12): 1) stoutly ventrally (Fig. 9). Wings hyaline with sickle-shaped body, with three apical hyaline to yellow veins. teeth not in same plane; 2) straight me- Metasoma: Node of petiole short in dial blade forming 0–5 teeth that de- lateral view with acute dorsum (Fig. 9); crease in size dorsally. Ventral border of anterior face not sharply separated from labrum weakly concave with ventral thick peduncle, posterior face perpen- corners rounded (Fig. 12). Labrum dicular laterally, gently curving medially bearing 2–3 coarse isolated spinules near 320 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON each ventrolateral corner. Maxilla with are very similar and in some cases are sclerotized band between cardo and sti- indistinguishable between species with- pes. Labium with patch of spinules dor- out a reference collection. Some gyne sal to palpus. Labium with small lateral characters such as pilosity or sculpturing sclerotized bands. Opening of sericteries are highly variable, as they are for a long transverse slit (Fig. 12). workers, but sometimes can be useful. Body: Stout. Prothorax bent ventrally Size, coloration, and head shape are also at right angles forming very short stout of some use in identification of the neck. Remainder of body straight. Ab- gynes. Coloration and size of males tend dominal diameter greatest at fourth to be very similar for many species, somite. Both ends of body broadly making these characters of limited value rounded. Dorsal profile of body curved, for identification purposes. Some spe- ventral surface nearly flat. Anus ventral. cies, however, have reliable male sculp- Leg and wing precursors present. Seg- ture characters. mentation indistinct. Integument of Geographical distribution can be use- ventral surface of thorax and first three ful for identifying fire ants but can be abdominal somites with few short biased by several factors. As mentioned transverse rows of minute spinules. by Trager (1991), fire ants are easily Body setae numerous, short, and uni- transported to new regions, which makes formly distributed. Body setae of two geographical information valuable only types: 1) simple, slightly curved with as a complement to other data. Also, the alveolus and articular membrane, 4–12 available distributional data for most in transverse row on ventral surface of species are patchy and are almost cer- each thoracic somite and anterior ab- tainly incomplete; therefore, some spe- dominal somites; 2) bifid, branches more cies could have much broader ranges or less perpendicular to base, tips re- than are reported here. On the other curved occurring on various regions of hand, occurrence records for fire ants are body; often setae posterior to head on often incorrect due to misidentifications thoracic dorsum differ slightly from or habit of assigning specimens to the other setae. Setae on ventral surface with most common species (e.g., S. invicta or alveolus and articular membrane. S. saevissima) and reported ranges can Length: Approximately 2.3–3.8 mm. hence be grossly overestimated. We there- Comments.—Indices calculated from fore deliberately omitted use of other adult measurements are provided for sources (Antweb, Antmaps) in the con- gynes and males in Tables 5 and 6, struction of maps to avoid aforemen- respectively. tioned errors. Consequently, we present Identification of fire ants.—The maps as conservative range estimates characters used here for the identifica- based mainly on our own collections tion of fire ants are those normally used and, when feasible and sufficiently dif- for myrmecological taxonomic work. ferent from our collections, the type lo- The most useful characters for the calities. For rarer species (e.g., S. pythia, workers are size, coloration, head shape, S. weyrauchi, or S. electra), we also in- and postpetiolar shape. After thorough cluded reliable collection site records examination of males and gynes, we feel from Trager (1991). that the workers are superior to sexuals In this work, an effort was made to for distinguishing the various species. follow the format of the descriptions The gynes and males of many species of prior Solenopsis authors to facilitate VOLUME 120, NUMBER 2 321 future systematic work on the group. As of Creighton (1930), and larval de- such, adult worker descriptions follow scriptions follow the format of Wheeler the format of Trager (1991), adult male and Wheeler (e.g., Wheeler and Wheeler and gyne descriptions follow the format 1976, 1986).

KEY TO THE SOLENOPSIS SAEVISSIMA SPECIES-GROUP (Modified from Trager 1991) This key is not intended for the identification of minor workers. To fully utilize all of the available information and to obtain an accurate identification, one should take a sizeable sample of workers, males, gynes and larvae from a colony. Special effort should be made to obtain major workers. A positive identification may be impossible for colonies lacking such individuals, such as those sampled soon after founding. Tabular keys to the major workers, gynes, and males are presented in Tables 1, 2, and 3, respectively. These should be consulted especially when a colony sample doesnotincluderepresentativesofallforms.

1. Gyne and male: small, 5.0 mm or less in length; sculpture reduced, body polished; meta- pleuron fused to propodeum. Gyne: parapsidal lines absent; clypeus lacking longitudinal carinae and apical teeth (Fig. 196); posterior margin of head broadly emarginated with posterolateral corners angulate (see below and Fig. 195) (social parasites lacking workers) ...... 2

Photo of casent0911238 by Alexandra Westrich. From www.antweb.org [Accessed 20 July 2017].

– Gyne and male: larger, greater than 5.0 mm in length; sculpture not reduced, present at least on propodeum, petiole and postpetiole; metapleuron not fused to propodeum. Gyne: parapsidal lines present; clypeus with longitudinal carinae terminating in teeth apically (Figs. 20, 22, 24, etc.); posterior margin of head narrowly emarginated medially with pos- terolateral corners rounded (see below and Figs. 20, 22, 24, etc.) (free living with workers) ...... 3 322 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Photo of casent0104504 by April Nobile. From www.antweb.org [Accessed 20 July 2017].

2(1). Gyne: posterior margin of head angulate (see below and Fig. 195), lobate in lateral view (Fig. 196). Distribution: south from Mato Grosso do Sul, Brazil to Buenos Aires Province, Argentina (Fig. 203) ...... S. daguerrei

– Gyne: posterior margin of head rounded, not lobate in lateral view. Distribution: Jacarepagua´, Rio de Janeiro, Brazil southwest to Rolaˆndia, Parana´,Brazil ...... S. hostilis

3(1). Major worker: pronotum low and nearly flat or weakly convex in profile (see below); metasoma black, legs yellow (yellowish brown in darker specimens), head and mesosoma ranging from clear yellowish red with some black or brownish black markings in the occipital area to uniformly brownish black (especially in vicinity of Cochabamba, Bolivia). Distribution: northwestern Argentina to Bolivia in Andean foothills (Fig. 201) . . . . S. electra VOLUME 120, NUMBER 2 323

Drawing by James Trager. From Trager 1991 J. New York Entomol. Soc. (Fig. 42).

– Major worker: pronotum higher, angular or strongly convex in profile (see below); color variable but never with metasoma completely black and with yellow legs ...... 4

4(3). Major worker: area immediately posterior and dorsal to metapleural spiracle finely punctate or striato–punctate (see below and Fig. 140); largest major workers with head strongly cordate (see below and Fig. 141). Male: weak to distinct mesonotal maculations present; ocelli moderate to large, OOI 0.80–1.26, normally OOI<1.00 (Fig. 65). Distribution: southern half of Mato Grosso, western Mato Grosso du Sul, Brazil (Fig. 203) ...... S. pusillignis

– Major worker: area surrounding metapleural spiracle shiny and smooth (see below and Figs. 130, 132, 134, 136, 138, 142, 144, 146); largest major workers with head moderately 324 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

(see below and Figs. 131, 133, 137, 139) to weakly cordate (Figs. 135, 143, 145, 147). Male: mesonotal maculations absent; male ocelli moderate to small, OOI > 1.00 (Figs. 57, 59, 61, 63, 67, 69, 71) ...... 5

5(4). Major worker: posterior face of postpetiole as high or higher than broad (see below) . . . . . 6

– Major worker: posterior face of postpetiole broader than high (see below) ...... 11

6(5). Major worker: pronotal dorsum in posterodorsal view medially concave; anterolateral bosses giving squared-off appearance to anterodorsal rim of pronotum (see below); head uniformly VOLUME 120, NUMBER 2 325

brownish black; mandibles usually brownish yellow; frons without dark median streak or this barely distinct from remainder of frons. Male: often with distinct tuberculate postpetiole, tubercle height ³ 1.5X width at base, tubercles glabrous; OOI < 1.35. Distribution: south- eastern Brazil to central eastern Argentina (Fig. 203); introduced into southeastern United States ...... S. richteri

Photo of casent0103101 by April Nobile. From www.antweb.org [Accessed 20 July 2017].

– Major worker: pronotal dorsum in posterodorsal view usually flat or weakly convex; pro- notum lacking anterolateral bosses (see below); or if bosses present, head yellowish, at least near mandibular bases and clypeus and often more extensively yellowish; Male: often lacking distinct tuberculate postpetiole, tubercle height £ 1.5X width at base, tubercles granulate or rugose; OOI > 1.4 ...... 7

Photo of casent0005804 by www.antweb.org [Accessed 20 July 2017].

7(6). Major worker: median streak (frontal streak, fs) usually present (see below and Fig. 50). Gyne: mesonotal maculations present (Fig. 52) (gyne of S. weyrauchi was not examined) ...... 8 326 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

– Major worker: median frontal streak usually absent (see below). Gyne: mesonotal macula- tions usually absent ...... 10

8(7). Major worker: large with DML exceeding 1.75 mm (sometimes over 2.0 mm) in largest workers of most series; piligerous foveolae small (<0.01 mm, see below). Gyne: if T1 maculation present, it sometimes has distinctly defined posterior margin. Distribution: nor- mally lowlands species in western Argentina and Bolivia (Fig. 202) ...... S. interrupta VOLUME 120, NUMBER 2 327

– Major worker: small with DML rarely in excess of 1.7 mm in even largest workers of most series (rarely up to 1.80 mm); piligerous foveolae large (0.005–0.03 mm, see below); Gyne: if T1 maculation present, it lacks a distinctly defined posterior margin (gyne of S. weyrauchi was not examined). Distribution: normally high elevation species ...... 9

9(8). Major worker: cephalicpiligerousfoveolaesmall(<0.01 mm); rear face of postpetiole with striae present on lower 0.50–0.75 (see below);mandibleswith5–6costulae; katepisternum of mesopleuron not or only weakly defined dorsally by finely striate furrow. Gyne un- known. Distribution: Peruvian, Bolivian, and Argentinian Andes, 2,000–3,500 m elevation (Fig.201) ...... S. weyrauchi 328 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Drawing by James Trager. From Trager 1991. J. New York Entomol. Soc. (Fig. 81).

– Major worker: cephalic piligerous foveolae large (0.01–0.03 mm); scape long, almost reaching the vertex of the head; rear face of postpetiole with striae present on lower 0.25– 0.33 and smooth and shiny upper (see below and Fig. 19); mandibles with 10–12 costulae, weak to obsolescent medially; katepisternum of mesopleuron weakly to distinctly defined dorsally by finely striate furrow (Fig. 18); promesonotal suture angulate medially, sometimes projecting upward (Fig. 18); first sternite of gaster with anterior projections, visible in dorsal view. Gyne: large piligerous foveolae (0.01–0.03 mm) present on head; interfoveolar areas of head striate; ocellar triangle striate (Fig. 20); median cell open by loss of m-cu cross vein (Fig. 89); postpetiole glabrous on upper 0.75 (Fig. 44). Distribution: southern and south- eastern Brazil, northeastern Argentina (Fig. 201) ...... S. metallica n. sp.

10(7). Major worker: larger, DML 1.4–l .6 mm (rarely 1.7 mm) in large workers; piligerous fo- veolae usually very small, inconspicuous. Gyne: cephalic pilosity approximately 0.30–0.33 mm long; metasoma pilosity arising from small, inconspicuous foveolae; median furrow on posterior 0.33 or less of mesonotum; bidentate metasternal process present. Larger species. Distribution: Orinoco drainage, Guianas, Amazonia and along rivers in bordering regions, also southeastern and eastern Brazil (Fig. 201) ...... S. saevissima VOLUME 120, NUMBER 2 329

– Major worker: smaller, DML < 1.4 mm in even the largest workers; piligerous foveolae on head and pronotum sometimes conspicuous, 5–l0X as wide as base of seta. Gyne: cephalic pilosity about 0.15–0.20 mm long (Fig. 53); metasoma pilosity arising from conspicuous piligerous foveolae nearly or actually as large as those of head and mesosoma (Fig. 51); median furrow on posterior 0.33–0.50 of mesonotum (Fig. 51); bidentate metasternal pro- cess absent. Smaller and much rarer species. Distribution: Mato Grosso do Sul to south- eastern Brazil and Misiones, Argentina (Fig. 202) ...... S. pythia

11(5). Major worker: smaller, DML rarely in excess of 1.70 mm in even largest workers of most series; median (frontal) streak (fs) present (see below). Gyne: frontal streak present (as in Fig. 50), sometimes faint; postpetiole usually completely sculptured, only extreme dorsum lacking striae (Fig. 42). Male: head usually completely granulate, shagreened; gena moderately to coarsely rugose. Distribution: lowland species, western Amazonia, south through Mato Grosso, eastern Bolivia, Paraguay and southeastern Brazil to Santa Fe Province, Argentina (Fig. 203); introduced into Southern United States ...... S. invicta

– Major worker: larger, DML exceeding 1.75 mm (up to over 2.0 mm) in largest workers of most series; median frontal streak usually absent (see below). Gyne: median frontal streak usually absent; postpetiole usually completely sculptured, only highest portion lacking striae (Figs. 41, 43). Male: head usually incompletely granulate, glabrous anterolaterally of median ocellus, not shagreened; gena striate to granulate ...... 12 330 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

12(11). Major worker: color mainly red to orange; mesosoma pilosity usually decumbent, not curved; transverse striae or rugae on rear face of postpetiole usually lacking, or faint, punctate or shagreened (see below); outer surface of mandible usually shining medially, costulae obso- lescent. Distribution: Uruguay, Entre Rios Province and adjacent parts of bordering provinces in Argentina; apparently introduced at Cochabamba, Bolivia (Fig. 202) . . . S. macdonaghi

Drawing by JamesTrager. From Trager 1991 from J. New York Entomol. Soc. (Fig. 63).

– Major worker: color brown to nearly black; mesosoma pilosity erect, longest setae usually curved; sculpture on rear face of postpetiole with conspicuous transverse striae or rugae on lower 0.66–0.75, punctate or shagreened (see below); outer surface of mandible with costulae, sometimes obsolescent medially ...... 13 VOLUME 120, NUMBER 2 331

13(12). Major worker: small with HL 1.45–l .55 mm; eye of largest workers relatively (and often absolutely) larger, REL 0.18–0.20 in large majors; head mostly dark brown to brownish black; in contrast, distal portion of clypeus, head near base of mandible, and (usually) area around dark median frontal sulcus distinctly lighter yellowish brown. Male: lateral faces of scutellum weakly to distinctly striate. Distribution: Buenos Aires and La Pampa Provinces, Argentina, Uruguay, north to Santa Catarina, Brazil(Fig.202) ...... S. quinquecuspis

– Major worker: large with HL 1.6–1.75 mm in largest workers; eye of largest workers relatively (and often absolutely) smaller than above species, REL 0.16–0.18 in large majors; head uniform reddish brown or gradually fading anteriorly to a slightly lighter reddish brown; distal portion of clypeus, sides of head anterior to eye, and frons faintly or not at all chromatically distinct from posterior portions of head, median frontal streak absent or very faint. Male: lateral faces of scutellum glabrous. Distribution: Southern Brazil(Fig.202) ...... S. megergates

DESCRIPTIONS Holotype.—Brazil: Santa Catarina State, Rt.166 ca 22 km north of Santa Solenopsis metallica Pitts, Camacho, Cecilia, Serra Geral, 1200 m, .xi.1998, Gotzek, McHugh, and Ross, K. G. Ross, M. C. Mescher, D. D. new species Shoemaker, and L. Keller, n. G-84 [USNM: 1 worker, USNMENT01126728]. urn:lsid:zoobank.org:act:D0AC4A84- Paratypes.—Brazil: Santa Catarina 95B8-4E9D-9FA9-FBB76636ABDA State, Rt.166 ca 22 km north of Santa (Figs. 16–20, 44, 89) Cecilia, Serra Geral, 1200 m, .xi.1998, K. G. Ross, M. C. Mescher, D. D. Solenopsis altipunctata Pitts, 2002: 63. Shoemaker, and L. Keller [MZSP: 1 worker, Nomen nudum. G-83, USNMENT01126729], [DZUP: 1 Solenopsis species ‘A’: Krieger and Ross worker, G-84, USNMENT01126730], 2005; Shoemaker et al. 2006. [EMUS: 1 worker, G-84, USNMENT- Solenopsis altipunctata Gotzek et al. 01126731], [UGCA: 1 worker, G-83, 2007. Nomen nudum. USNMENT01126732]. Brazil: Parana´ Solenopsis saevissima ‘southern high- State, Edge of Ponto Grossa, median of lands’: Ross et al. 2010. Rt.PR-513, 20.xi.2015, G. Camacho and 332 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

D. Gotzek, n. PR15-084 [USNM: ommatidia. Scape curved basally, thickest 1 male, USNMENT01126733; 1 gyne, subapically. Apex of scape in repose not USNMENT01126734]. surpassing posterior border of head. Diagnosis of major worker.—Head Mesosoma: Anterodorsal pronotal bor- broad, cordate (Fig. 16). Head sculpture der, weakly convex (Fig. 18). Anterolateral with large piligerous foveolae, 0.01–0.03 pronotal corners variously rounded, mm in diameter. Median frontal streak never distinctly angulate and bearing present. Median ocellus absent (Fig. 16). slight humeral bosses. Promesonotal Scape long, almost reaching the vertex of suture angulate medially with small the head. Mandibular costulae well de- dorsal projection at apex (Fig. 18). Pro- veloped throughout entire length. Meso- notum with steep anterior declivity dis- notum with 30–36 setae. Promesonotal tinguished from dorsum with slight break suture in largest major workers angulate in outline at point of anterior mesonotal medially, sometimes projecting upward projection. Metanotal impression con- (Fig. 18). Propodeum sculpture glabrous spicuous, set off by steep, coarsely striate, posteroventral to spiracle (Fig. 18). Post- posterior mesonotal and anterior propo- petiole shape as high as or higher than deal declivities (Fig. 18). Propodeum broad (Fig. 19). Postpetiole sculpture in with dorsal face slightly convex, curving posterior view with lower 0.25–0.33 evenly into declivous face. Propodeum transversely rugose, upper surface glabrous angulate posterolaterally due to slight and shiny (Fig. 19); first gaster sternite with longitudinal, posterolateral bosses. Mes- anterior projections, visible in dorsal view. opleural katepisternum defined dorsally Major worker.—Head: Cordate, slightly by finely striate impression (Fig. 18), longer than broad, widest posterior to eyes, weakly defined in some specimens. sides weakly convex (Fig. 16). Posterior Metasoma: Petiolar peduncle notably border of head with concave median im- to slightly shorter than base of node. pression, concavity 0.5X as wide as dis- Postpetiolar node globular to sub- tance between apices of frontal lobes. rectangular with dorsum convex, lateral Lower edge of anterior border of clypeus faces straight, parallel to convergent bearing large median seta borne on weakly ventrally. Postpetiole, as seen from be- developed median tooth, tooth is absent in hind, with height greater than width. some specimens (Fig. 16). Clypeal cari- Pilosity: Composed of yellow setae. nae, strongly developed, divergent distally, Longer setae curved. Mesonotum usually projecting as triangular teeth that are no- with 30–36 erect setae. Mesopleuron with tably larger than median tooth and much several dorsal setae. Longest setae on larger than paracarinal teeth (Fig. 16). metasomal dorsum usually at least 3–4X Paracarinal teeth reduced in some speci- length of shortest. Suberect pubescence mens. Carinal and paracarinal teeth more present on cervical flange of pronotum, dorsally on clypeal border than median on anterior face of petiolar nodes, and on tooth (Fig. 16). Mandible with normal propodeal dorsum. curvature (Fig. 16), four teeth (Fig. 16), Sculpturing: Integument with distinct and 10–12 fine costulae, weakly de- piligerous foveolae present on head, meso- veloped or obsolescent medially, apically soma and petiole, 0.01–0.03 mm in diameter becoming broader with shallower inter- (conspicuous even in minors). Piligerous costular furrows on upper surface. Eye foveolae conspicuous but smaller on legs. ovate, with maximum diameter 10–12 Interstitial area smooth, shiny. Sculpture ommatidia, and minimum diameter 6–7 of metapleuron consisting of longitudinal VOLUME 120, NUMBER 2 333 striae. Posterior face of petiole with striae Coloration, Sculpturing, and Pilosity. on basal 0.25. Posterior face of postpetiole Piligerous foveolae large, width 0.01– with transverse striae on basal 0.25, upper 0.03 mm in diameter, larger on head than 0.75 glabrous with several conspicuous on thorax and abdomen. Pubescence piligerous foveolae (Fig. 19). simple, yellow and erect, longer and Coloration: Color varies from yellow- denser on head than elsewhere, longest orange with brown metasoma and with T1- on anterior edge of clypeus. Mesosoma T4 lighter anteriorly to brown-red dorsally with longest pubescence (length >0.30 with ventral portion of head and legs or- mm) 2X longer than shortest pubes- ange, and T1 with apical margin orange. cence. Mandible with 7–8 coarse, dis- Some specimens with darker medial por- tinct costulae present throughout entire tions of leg segments. Median streak length. Propodeum with fine striae pos- present, but faint in some specimens. teriorly, anterior 0.25% polished. Petio- Morphometric Measurements: HL lar node with 0.25 coarsely striate, 1.14–1.31, HW 1.00–1.24, SL 0.91– remainder polished. Lower 0.25 of pos- 1.06, EL 0.17–0.20, PW 0.59–0.70, terior face of postpetiole granulate to DML 1.48–1.70, CI 0.90–0.95, SI 0.80– striato-granulate, upper 0.75% of surface 0.86, REL 0.14–0.16, N=21, (HL 1.21, polished (Fig. 44). Area between ocelli HW 1.14, SL 0.94, EL 0.18, PW 0.62, coarsely striate, sometimes drastically DML 1.61, CI 0.94, SI 0.83, REL 0.15). so. Interfoveolar spaces on head finely Gyne.—Head: Broader than long, striate. Remaining integument smooth quadrate, wider dorsal to eyes than ventrally, and polished. Color orange with black sides of head convex from eyes to occipital mesonotal maculations present ante- angles, curving inwards to mandibular base romedially and around parapsidal lines. (Fig. 20). Eye sometimes with 1–4 setae Dorsal transverse band dark brown on protruding from between ommatidia, pronotum and mesopleuron. Metasoma setae £ 3X length of ommatidium. Ocelli dark brown, except petiole ventrally and small (Fig. 20). Median ocellus circular to basal 0.25% of T1 and S1 orange blend- slightly elliptical; lateral ocelli ovate, smaller ing to dark brown apically. Leg segments than median ocellus (Fig. 20). Clypeus orange, brown medially. Sometimes T1 projecting, carinal teeth stout and sharp, base completely dark brown. Internal carinae well defined, less so dorsally, greatly margins of ocelli dark brown. divergent ventrally (Fig. 20). Paracarinal Morphometric Measurements. L teeth small, sometimes poorly defined. ;6.1–6.4, HW 1.30–1.40, VW 0.80–0.85, Median clypeal tooth poorly developed to HL 1.10–1.15, EL 0.31–0.36, OD 0.19– absent (Fig. 20). Approximately 0.33% of 0.22, OOD 0.16, LOW 0.04–0.06, MOW eye dorsal to midpoint of head (Fig. 20). 0.07–0.09, CD 0.19–0.22, MFC 0.13– Mesosoma. Narrower than head, ro- 0.15, EW 0.29–0.36, SL 0.90–1.01, PDL bust, ovate. Parapsidal lines present on 0.14–0.16, LF1 0.08–0.11, LF2 0.07–0.10, posterior 0.50 to 0.75 of disk. Meso- LF3 0.07–0.10, WF1 0.05–0.08, FL 1.10– notum without posteromedian furrow. 1.20, FW 0.19–0.30, MW 1.15–1.31, Median bidentate process present on DLM 2.34–2.51, PRH 0.93–1.10, PL metasternum. Wing venation as in Fig. 89, 0.60–0.70, PND 0.55–0.65, PH 0.55–0.65, m-cu cross vein absent, medial cell open. PPL 0.25–0.35, DPW 0.50–0.65, PPW Metasoma. Lateral faces of postpetiole 0.66–0.74, PHB 0.34–0.44, N=2. strongly to slightly concave. Petiolar spi- Male.—Head. Trapezoidal. Eye very racle tuberculate in some cases. large, strongly convex, ovate, occupying 334 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON more than 0.5X side of head, anterior 0.14, LF1 0.21, LF2 0.15, LF3 0.17, WF1 border not reaching insertion of mandi- 0.08, FL 0.41, FW 0.23, MW 0.96, DML ble. Ocelli large, prominent. Anterior 2.4, PL 0.6, PND 0.5, PH 0.43, PPL 0.48, edge of clypeus convex. In lateral view, DPW 0.62, PPW 0.72, PHB 0.51, CI 1.28, clypeus shows small, blunt, beak-like OI 0.79, REL 0.55, OOI 1.09, VI 0.52, central lobe directed anteriorly. Mandi- FCI 0.25, CDI 0.36, SI 0.12, SI2 0.27, SI3 ble linear, with two large teeth. Antennal 0.8, FI 0.56, NI 0.83, PLI 0.72, PHI 0.89, scape ;1.3X as long as broad, cylin- PWI 1.03, PPWI 1.5, PPWB 1.41. drical. Pedicel subglobose, broader than Fourth instar worker larva.—Head. scape or following flagellomere. Large, subpyriform in anterior view Mesosoma. Robust, elliptical. In lateral (height 0.43 mm, width 0.45 mm) (Figs. view, mesonotum flat, at the same level as 148, 151). Cranium slightly broader than the pronotum. Scutellum swollen and long (Figs. 148, 151). Antenna with 2 or strongly convex, higher than mesonotum. 3sensilla,eachbearingspinule(Figs.148, Propodeum rounded, basal face strongly 151). Occipital setal row with 7–8 bifid convex transversely, only slightly convex setae, base 0.5–0.8X total length of seta, longitudinally, declivous face flat and per- setae 0.07–0.16 mm long (Figs. 148, pendicular. Posterior margin of meta- 150, 151). First setal row on vertex with pleuron separated from propodeum by 2 bifid setae, base ;0.66X total length of asutureandventralmarginsofmetapleuron seta, 0.10 mm long (Figs. 148, 151). fused to propodeum. Wing venation similar Second setal row on vertex with 4 setae, to the male of S. invicta,asinFig.95. inner 2 setae simple, outer 2 setae with Metasoma.Anteriorfaceofpetiole bifid apices (base ;0.66X length), 0.10– gently sloping, posterior face parallel. 0.15 mm long (Figs. 148, 151). Setae In lateral view, postpetiole globulose, ventral to antenna level simple, 0.15– wider than petiole. Dorsum of petiole 0.17 mm long (Figs. 148, 151). Clypeus with a strong median longitudinal im- with row of 3–4 setae, inner setae shorter pression, forming two lateral lobes. than outer setae, 0.05–0.10 mm long Petiole anteroposteriorly flattened, bi- (Fig. 148). Labrum small, short (width 2X lobate. Postpetiole wider than petiole, length) (Figs. 148, 151). Labrum with 4–5 ventral surface flat. Postpetiolar spira- minute sensilla and 2 setae on dorsal sur- cles high, strongly projected laterally. face of each half and apical border with Genitalia as in S. invicta (e.g. Fig. 75). 3–6 sensilla on each half. Labrum with 2– Coloration, Sculpturing, and Pilosity. 3coarseisolatedspinulesneareachven- All sculpture lacking except for basal 0.25 trolateral corner. Straight medial portion of petiole and postpetiole, metapleuron of mandible with 2–5 teeth that decrease in and sides of propodeum finely striate and size dorsally (Fig. 149). Maxilla with apex punctuated. Body smooth and polished. conical, palpus peg-like with 5 sensilla, Setae golden, suberect, distributed all over each bearing one spinule. Galea conical the body. Mesonotal pubescence absent. with 2 apical sensilla, each bearing one Color black except legs and gaster brown. spinule. Labium with patch of spinules Wings and veins light brown. dorsal to each palpus, spinules coarse and Morphometric Measurements.Lisolated or in short rows of 2–3. Labial ;5.44, HW 1.02, VW 0.52, HL 0.8, EL palpus slightly elevated with 5 sensilla, 0.44, OD 0.11, OOD 0.12, LOW 0.11, each bearing one spinule. MOW 0.12, CD 0.29, MFC 0.26, EW Body. Spiracles small, first spiracle 0.35, SL 0.12, SW 0.11, PDL 0.08, PEW larger than others. Body setae of 2 types. VOLUME 120, NUMBER 2 335

Simple setae (0.05–0.10 mm long) ar- suburb to Rt.PR-170)”, 24.xi.2015, ranged in transverse row of 6–9 on ventral -25.392934, -51.49619398, G. Camacho surface of each thoracic somite and on and D. Gotzek, PR15-153, (4 w); “Candoi, each of 3 anterior abdominal somites, empty lot in town center”, 24.xi.2015, some with short denticulate tips. Bifid -25.56748403, -52.05006, G. Camacho setae (0.06–0.09 mm long) occur else- and D. Gotzek, PR15-161, (2 w); “Pinhao, where, base 0.5X length. town park”, 24.xi.2015, -25.69448998, Length. Approximately 2.6–2.8 mm. -51.660301, G. Camacho and D. Gotzek, Material examined.—Argentina: PR15-165, (8 w); Rt.BR-277 btwn Missiones, Aristo´bulo del Valle, 23. Guarapuava + Irati, 25.xi.2015, -25.31583399, v.2015, 27°05.2359, 54°57.1689 (19 w). -51.19612, G. Camacho and D. Gotzek, Brazil: Parana´: “Pinhais, R. Rod. Dep. PR15-194, (6 w); National Irati, 26. Joao Leopoldo Jacomel”, 18.xi.2015, xi.2015, -25.40887697, -50.57687396, G. -25.43045098, -49.20909698, G. Camacho and D. Gotzek, PR15-211, (26 Camacho and D. Gotzek, PR15-036, w); “Pinheiros, edge of soccer field”, 26. (4 w); “Curitiba, Barigui Park”, 19. xi.2015, -25.42351797, -50.55518403, G. xi.2015, -25.42987799, -49.31599097, Camacho and D. Gotzek, PR15-224, G. Camacho and D. Gotzek, PR15-039, (2 w); Rt.BR-153 btwn Irati + Unia˜od. (18 w); “Rt.BR-277, Campo Largo, Vitoria, 26.xi.2015, -25.68580499, Metalurgica Gans factory, field and -50.76397598, G. Camacho and D. roadside by factory”, 19.xi.2015, Gotzek, PR15-226, (4 w); Rt.BR-153 exit -25.43349998, -49.41256902, G. to Rio Azul, 26.xi.2015, -25.70675304, Camacho and D. Gotzek, PR15-051, (10 w); -50.78334597, G. Camacho and D. “Rt.BR-277, Campo Largo, Metalurgica Gotzek, PR15-228, (10 w); “Mallet, town Gans factory, on hillside next to road; center, recently mowed field”, 26.xi.2015, ;3m from PR15-067”, 19.xi.2015, -25.88597297, -50.83851499, G. Camacho -25.43395202, -49.41203199, G. and D. Gotzek, PR15-233, (16 w); “Paula Camacho and D. Gotzek, PR15-066, Freitas, in front of medical center”, 26. (4 w); “S. Luis do Puruna˜, open gravel xi.2015, -26.11710403, -50.82043698, G. field behind truck stop on Rt.BR-277”, Camacho and D. Gotzek, PR15-240, (4 w); 20.xi.2015, -25.47302401, -49.70426696, Rondinha, 26.xi.2015, -26.171502, G. Camacho and D. Gotzek, PR15-075, -50.91157199, G. Camacho and D. Gotzek, (4 w); “S. Luis do Puruna˜, open gravel PR15-242, (2 w); Unia˜odaVitoria,26. field behind truck stop on Rt.BR-277”, xi.2015, -26.20269299, -51.06220803, G. 20.xi.2015, -25.47300699, -49.70436101, Camacho and D. Gotzek, PR15-249, (2 w); G. Camacho and D. Gotzek, PR15-076, “Palmeira, Rt.BR-277”, 27.xi.2015, (2 w); “Edge of Ponto Grossa, median of -25.43500604, -49.991854, G. Camacho Rt.PR-513”, 20.xi.2015, -25.14492497, and D. Gotzek, PR15-255, (4 w); Colonıˆa -50.14723303, G. Camacho and D. Gotzek, Johannesdorf on Rt.BR-476, 27.xi.2015, PR15-082, (6 w); “Vila Velha N.P., -25.742842, -49.76574504, G. Camacho Campos Gerais open shrubland”, 21. and D. Gotzek, PR15-264, (2 w), Rt. xi.2015, -25.25196397, -50.008018, G. BR-476 btwn Lapa + Sao Mateus do Sul, Camacho and D. Gotzek, PR15-086, 27.xi.2015, -25.85078599, -49.94710797, (6 w); “Rt.BR-376, side of road”, 21. G. Camacho and D. Gotzek, PR15-268, xi.2015, -24.87010701, -50.44417997, (10 w); “Rio Negro, Rt.BR-116”, 28. G. Camacho and D. Gotzek, PR15-093, xi.2015, -26.070288, -49.73545603, G. (2 w); “Cascavel (Guarapuava, southeastern Camacho and D. Gotzek, PR15-275, (4 w); 336 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

“Campo do Tenente, town center”, 28. Etymology.—This species is named for xi.2015, -25.97824599, -49.68351698, G. one of its most common and conspicuous Camacho and D. Gotzek, PR15-282, (6 w); color morphs, the bright, metallic orange “Colombo, Rt.BR-476 to Tunas”, 29. phase. It is also one of several authors’ xi.2015, -25.32895703, -49.15940403, G. favorite rock bands. The specific epithet is Camacho and D. Gotzek, PR15-308, anouninapposition. (12 w); “Rt.BR-476, edge of Bocaiuva Distribution.—The type series of the do Sul”, 29.xi.2015, -25.19912797, species was originally collected in the -49.11631904, G. Camacho and D. Gotzek, highlands of Santa Catarina state, southern PR15-317, (2 w); “Rt.BR-476, btwn Brazil. Further examination of material Bocaiuva do Sul + Tunas”, 29.xi.2015, collected in Rio de Janeiro State in 2008 -25.18001899, -49.12016901, G. Camacho and Misiones Province in 2015 also proved and D. Gotzek, PR15-318, (6 w); “Tunas, to be S. metallica,suggestingasoutheast- town center”, 29.xi.2015, -24.97498498, ern Atlantic Forest range for the species. In -49.08486804, G. Camacho and D. Gotzek, 2015, extensive collections in Parana´ State PR15-321, (14 w); “Rt.BR-476, btwn showed that the species is widely distrib- Tunas + Bocaiuva do Sul”, 29.xi.2015, uted in subtropical humid forest in the re- -25.01404096, -49.07943397, G. Camacho gion. See Fig. 201. and D. Gotzek, PR15-330, (18 w); Comments.—The major workers of “Colombo, town center, along Rt.BR-476”, this species are easily distinguished from 29.xi.2015, -25.30889997, -49.14433798, others in this species-group by the long G. Camacho and D. Gotzek, PR15-341, scape failing to reach the vertexal margin (2 w); Rt 277 @ KM 493; near Guaraniacu, of the head, postpetiole sculpture in pos- 1998, -25.107, -52.867, G-72, (1 w); Rt 116 terior view with lower 0.25–0.33 trans- at Rio Negro, 1998, -26.10583333, versely rugose, upper surface glabrous and -49.7975, G-80, (2 w); Rt 277 @ KM 317; shiny and the anterior projection on the at junction with Rt 373, 1998, -25.46, first gaster sternite visible in dorsal view. -51.958, G-74, (1 w); Palmas, 2009, Other distinguishing characters are present -26.484151, -51.991450, E. Fox, Bra09- on the gyne, including the greatly di- 22, (2 w). Brazil: Rio de Janeiro: Treˆs verging clypeal carinae, the large pilig- Rios, 2009, -22.118277, -43.209538, erous foveolae on the head and mesosoma, E. Fox, Bra09-15, (1 w); Itaipava, 2009, the strongly to weakly defined striae be- -22.383333, -43.133333, E. Fox, Bra09-31, tween the ocelli, the lack of a median cell (2 w); Rio de Janeiro University campus, due to the loss of the m-cu cross vein, and 2009, -22.911267, -43.236059, E. Fox, the reduction in postpetiolar sculpturing. Bra09-68, (1 w). The major workers of S. metallica can be Nomenclatural notes.—An unpublished easily differentiated from their putative manuscript name, “S. altipunctata”(Pitts sister species, S. weyrauchi. Solenopsis 2002), was used by Gotzek et al. (2007) in metallica have 10–12 costulae on the reference to this species. Since that usage mandible that are obsolescent medially and occurred without the species being for- have larger piligerous foveolae on the head mally described in a publication satisfying and mesosoma. In comparison, the major the requirements of ICZN Article 8, the workers of S. weyrauchi have 5–6 complete name was rendered unavailable as a nomen mandibular costulae and their cephalic fo- nudum following Article 13 of the Code veolae are smaller. The shape of the post- (ICZN, 1999). Here we formally describe petiole of the workers is most similar to that this species as Solenopsis metallica. of S. saevissima,butismorecoarsely VOLUME 120, NUMBER 2 337 sculptured. The darker colored workers Buenos Aires Province. Rosas. F. C. appear bicolored, which is similar to the Sud. MACN] color pattern of S. electra.Theminor Labauchena acuminata Borgmeier workers (Fig. 17) of this species are usually 1949: 208. [IMLA] lighter than the majors, but can sometimes Solenopsis daguerrei:Ettershank1966:140. have similar coloration. They also have large, distinct foveolae on the head and Gyne.—Head: broader than long, mesosoma, which is easily noticed. As with quadrate, wider anterior to eyes, sides of the other fire ant species, however, the mi- head weakly convex from eyes to oc- nors are difficult to identify. The larvae of cipital angles, nearly straight anterior to this species are unremarkable and are sim- eyes. Occipital angles well defined (Fig. ilar to S. saevissima and S. invicta by having 195), lobate in lateral view (Fig. 196). bifid setae on the head capsule. The setae on Vertex flattened posteriorly with narrow, the head capsule are longer in this species, transverse impression just anterior to however, than in S. invicta or S. saevissima. occipital carina. Occipital furrow lack- In addition to the morphological ing (Fig. 195). Frontal furrow lacking characters that define the species, (Fig. 195). Ocelli small, median ocel- S. metallica can be differentiated in the lus ventral to posterior margin of eyes field by ecological and behavior char- (Fig. 195). Clypeus not projecting, acteristics that are different from sym- lacking carinae or carinal teeth, ante- patric fire ant species. During collections rior margin straight. Mandible gently in Parana´ state in 2015, we observed that curving, masticatory border with one S. metallica presents a less aggressive large tooth and usually rudiments of response and sting to nest disturbance two more teeth, with dorsal lobe dorsal than S. invicta and other fire ants, apart to teeth rudiments (Fig. 197). Eye convex, from its usual bright orange or goldish ovate, midpoint of head reaches posterior appearance to the naked eye. It appears 0.33 of eye. Antennal scape in repose much more shade tolerant than S. invicta as surpasses lateral ocellus. Antenna 11-seg- it builds nests underneath closed canopy. mented. Pedicel ³ 2X length of second The taxonomic distinctiveness of flagellomere. First and second flag- S. metallica is also circumstantially ellomere length each >1.5X their width. supported by genetic data. DNA sequence Mesosoma. Elliptical, narrower than data (mitochondrial: Shoemaker et al. head. In lateral view, mesonotum convex 2006; Ross et al. 2010; nuclear: Gotzek anterior portion that greatly overhangs et al. 2007; Krieger and Ross 2005) and pronotum, lobate (Fig. 196), posterior half alargepanelofmicrosatelliteandallo- straight. Pronotum wider than mesonotum. zyme data (Ross et al. 2010) clearly Scutellum as high as mesonotum, flattened distinguish individuals of this species with short, perpendicular posterior face. (alternately termed S. sp. “A”, “southern Angle of propodeum well-defined, obtuse, highlands”, or “S. altipunctata”inthose differentiation between basal and decli- studies) from other fire ant species. vous faces indistinct (Fig. 198). Meso- sternum small, slightly rounded beneath. Solenopsis daguerrei (Santschi) Parapsidal lines absent. Posterior and ventral margin of metapleuron fused to (Figs. 86, 106, 108, 195–200) pronotum. Propodeal spiracle much re- Labauchena daguerrei Santschi 1930: 81. duced in size (Fig. 198). Metasternal bi- [Holotype (?) gyne, males. ARGENTINA. dentate median process present. Wing 338 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON venation reduced (Fig. 106), medial cell Dorsum of both with slight median lon- lacking or barely discernable as such. gitudinal impression. Petiole dorsolat- Metasoma. Petiolar node thick, dor- erally rounded, not bilobate. Postpetiole sum somewhat flattened at obtuse angle, wider than petiole, ventral surface flat. appearing to have anterior median boss Genitalia reduced in form, digitus lack- on dorsum. Petiole ventrally with me- ing setae, aedeagus with few ventral dian carina on anterior 0.50. Postpetiole teeth (Fig. 86). lacking ventral transverse carina, only Coloration, Sculpturing, and Pilosity. slightly convex. All sculpture lacking except for basal Coloration, Sculpturing, and Pilosity. 0.25 of petiole and postpetiole finely Sculpture lacking, body polished, except striate. Body smooth and polished. Setae posterior 0.25 of petiole finely striate. golden, suberect, length 0.10–0.16 mm, Setae long (0.10–0.28 mm), golden, mesonotum and petiolar nodes sparsely semi-erect, somewhat longer on meso- pubescent. Mesonotal pubescence sparse soma than elsewhere. Color yellow with (as in Fig. 72). Color yellow except apex of mandibles and apices of meta- vertex of head and gaster brown. Wings soma segments 3–6 brown. Internal and veins hyaline. margins of ocelli yellow. Material Examined.—See Appendix A. Male.—Head. Trapezoidal (Fig. 199). Distribution.—The known range of S. Eye very large, strongly convex, ovate, daguerrei extends from Buenos Aires occupying more than 0.5X side of head, Province, Argentina northward, including anterior border reaching insertion Uruguay, to Campo Grande, Brazil and of mandible (Fig. 199). Ocelli large, eastward to Sa˜o Paulo, Brazil (Fig. 203) prominent (Fig. 199). Anterior edge of (Briano et al. 1997). Solenopsis daguerrei clypeus straight (Fig. 199). In lateral seems to be generally sparse over most of view, clypeus shows small, blunt, beak- its range. They appear to be concentrated like central lobe. Mandible linear, with in colonies only in certain areas (Briano single apical tooth, lobe present dorsal to et al. 1997). tooth (Fig. 199). Antennal scape ;1.7X Comments.—The males and gynes of as long as broad, cylindrical (Fig. 200). this species are distinct from the other Pedicel subglobose, broader than scape members of the group by their colora- or following flagellomere (Fig. 200). tion, and the reduction in size, sculptur- Mesosoma. Robust, elliptical. In lat- ing, and wing venation associated with eral view, mesonotum swollen anteri- their socially parasitic existence. The orly, overhanging pronotum. Scutellum genitalia of the male are also distinct convex, slightly higher than mesonotum. from the other species by lacking setae Propodeum rounded, basal face strongly on the digitus, having a reduced number convex transversely, only slightly convex of ventral setae on the volsella, and longitudinally, declivous face flat and having a reduced number of ventral teeth perpendicular. Posterior and ventral mar- on the aedeagus (Fig. 86). gins of metapleuron fused to propodeum. Solenopsis daguerrei has been re- Wing venation reduced (Fig 108), many ported to either kill the host gyne in veins being nebulous. laboratory studies (Bruch 1930) or to Metasoma. Anterior face of petiole be an inquiline, allowing the host gyne gently sloping, posterior face abruptly to live (Silveira-Guido et al. 1965). curved. In lateral view, postpetiole Regardless of the outcome for the elongate, slightly shorter than petiole. host gyne, the parasite lowers the egg VOLUME 120, NUMBER 2 339 production of the host colony and some Postpetiole sculpture in posterior view speculation has been made regarding its with lower 0.66 transversely rugose, use as a biological control agent (Jouvenaz granulate, upper surface glabrous and 1990; Wojcik 1990). Regarding hosts, it shiny. Color of head, legs, antennae gen- is reported to parasitize S. invicta, erally red yellow. Mesosoma and gaster S. richteri, S. macdonaghi, and S. quin- dark brown. T1 yellow anteriorly. Man- quecuspis (Santschi 1930; Briano et al. dibles brown. Some specimens darker 1997; Calcaterra et al. 2000). We found brown black, with appendages slightly S. daguerrei only in S. invicta colonies lighter. during our extensive sampling in Bra- Gyne.—Head. Slightly broader to as zil and Argentina (see Appendix A). broad as long, quadrate, sides of head convex from eyes to occipital angles, straight anterior to eyes (Fig. 40). Eye Solenopsis electra Forel sometimes with 2–4 long setae pro- truding from between ommatidia, setal (Figs. 39, 40, 107) length >4X width of ommatidium. Ocelli Solenopsis pylades electra Forel 1914: large, prominent (Fig. 40). Median 397. [Syntype workers. ARGENTINA. ocellus circular, lateral ocelli slightly Salta. Jujuy. XI-913 (=1913). Schuer. ovate (Fig. 40). Ocelli in more anterior #129. MHNG.] position on head (Fig. 40). Clypeus pro- S. saevissima electra: Santschi 1916: jecting, carinal teeth stout and sharp, ca- 381. rinae well defined, prominent between S. (Solenopsis) saevissima electra: antennal scrobes, slightly divergent ven- Creighton 1930: 92. Worker, gyne. trally (Fig. 40). Paracarinal teeth small, S. saevissima saevissima cline S. sae- indistinct to absent (Fig. 40). Median vissima richteri (Bolivian variant): clypeal tooth well developed (Fig. 40). Wilson 1952: 65. [MCZ.] Approximately 0.50 of eye basal to mid- S. saevissima saevissima cline S. sae- length of head (Fig. 40). vissima richteri subsp. electra: Wilson Mesosoma. Parapsidal lines present 1952: 65. [MCZ.] on posterior half of disk (Fig. 39). S. electra: Trager 1991: 192. Mesonotum without posteromedian furrow. Metasternum with bidentate Worker.—Head subovate. Head median process. Wing venation as in sculpture with small piligerous foveolae, Fig. 107. <0.01 mm in diameter. Median frontal Metasoma. Lateral faces of post- streak absent. Median ocellus in largest petiole weakly concave. Petiolar spiracle major workers present. Mandibular cos- normally not tuberculate. Postpetiolar tulae well developed throughout entire spiracles normally tuberculate. length. In lateral view, pronotum low and Coloration, Sculpturing, and Pilosity. nearly flat to weakly convex. Meso- Piligerous foveolae small, sparse, width notum with 20–25 setae. Promesonotal <0.01 mm in diameter, larger on head suture in largest major workers gently than on thorax and abdomen. Pubes- curved medially, never projecting up- cence simple, golden and erect, longer ward. Mesonotum weakly convex in lat- and denser on head than elsewhere, eral view. Propodeum sculpture granulate longest on anterior edge of clypeus. posteroventral to spiracle. Postpetiole Mesonotum pubescence 0.16–0.25 mm, shape as high as or higher than broad. longest pubescence on mesonotum 2X 340 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON longer than shortest pubescence. Man- size than those of S. saevissima and dible with 5–8 coarse, distinct costulae S. macdonaghi. The gynes of S. electra present throughout entire length. Pro- differ from the gynes of the sister spe- podeum with fine striae throughout (Fig. cies, S. pusillignis, by having a smaller 39). Petiolar node basal 0.75 with striate, OI, a more developed median clypeal dorsum polished. Postpetiolar node basal tooth, and a darker coloration of the 0.50 with fine striae, dorsum polished. gaster. Remaining integument smooth and pol- The northern populations of S. electra ished. Color yellow with gaster red brown. have much larger workers than the T1 with basal 0.50 yellow, remaining southern populations, but the gynes of segments yellow anterolaterally. Internal these populations remain unchanged in margins of ocelli dark brown. size. Males were not available for ex- Morphometric Measurements. L amination for this study, but Trager ;6.2–6.5, HW 1.15–1.28, VW 1.09– (1991) describes them as being relatively 1.15, HL 1.20–1.30, EL 0.36–0.44, OD small compared to males of the rest of 0.15–0.21, OOD 0.09–0.12, LOW 0.10– the species-group. 0.15, MOW 0.10–0.16, CD 0.15–0.19, MFC 0.18–0.21, EW 0.25–0.34, SL Solenopsis interrupta Santschi 0.78–0.91, PDL 0.14–0.19, LF1 0.07– 0.11, LF2 0.05–0.10, LF3 0.07–0.10, (Figs. 21, 22, 47, 52, 56, 57, 73, 74, WF1 0.04–0.07, FL 0.92–1.05, FW 92, 93, 132, 133, 152–154, 157) 0.21–0.29, MW 1.21–1.33, DLM 2.15– Solenopsis saevissima var. interrupta 2.31, PRH 0.88–1.04, PL 0.56–0.68, Santschi 1916: 397. [Syntype (?) PND 0.45–0.56, PH 0.55–0.64, PPL workers. ARGENTINA. La Rioja. 0.31–0.36, DPW 0.50–0.68, PPW 0.56– Bajo Hondo. NHMB.] 0.64, PHB 0.32–0.45, N=2. S. (Solenopsis) saevissima interrupta: Male.—Unknown. Creighton 1930: 89 (In part.). Fourth instar worker larva.— S. interrupta Wilson 1952: 61 (In part.). Unknown. Material Examined.—Various speci- Worker.—Head weakly to strongly mens (FSCA). cordate (Fig. 132). Head and mesosomal Distribution.—The currently known sculpture with small piligerous foveolae, range of S. electra extends northward <0.01 mm in diameter. Median frontal from Santiago del Estero Province of streak mostly absent, but sometimes Argentina to Santa Cruz, Bolivia (Fig. distinctly darkened. Median ocellus in 201). Trager (1991) lists a sample exam- largest major workers absent (Fig. 133). ined from Asuncio´n, Paraguay. Sampling Mandibular costulae dense, present efforts between the known range and throughout, rarely partially obsolescent. Asuncio´n, Paraguay have not produced Mesonotum with 20–25 setae (Fig. 132). any specimens of S. electra,sothisrecord Promesonotal suture in largest major may represent an introduction. workers gently curved medially, never Comments.—The gyne of S. electra is projecting upward (Fig. 132). Propodeum similar to S. pusillignis, S. saevissima, sculpture glabrous posteroventral to spi- and S. macdonaghi in coloration and in racle (Fig. 132). Postpetiole shape as high the lack of mesonotal maculae. The gyne as or higher than broad. Postpetiole of this species has a thinner petiolar sculpture in posterior view weakly node, a smaller OOI, and a smaller body transversely rugose, weakly granulate, VOLUME 120, NUMBER 2 341 reaches dorsum only in largest workers. clypeus. Pubescence darker on darkly Color generally red yellow to brown maculated areas. Mesosoma with longest yellow, with head and mesosoma dorsum pubescence (length 0.30 mm or greater) darker. Gaster dark brown. T1 with 3X longer than shortest pubescence. maculation red yellow to brown yellow. Mandible with several coarse, 6–8, dis- Gyne.—Head: broader than long, tinct costulae present throughout. Pro- quadrate, slightly wider dorsal to eyes podeum with fine striae posteriorly, than ventral to them, sides of head con- anterior 0.25 polished to finely striate. vex from eyes to occipital angles, Petiolar node posterior surface with straight to nearly straight ventral to eyes lower 0.75 coarsely striate, dorsum (Fig. 22). Eyes sometimes with 3–4 setae finely striate. Postpetiolar node posterior protruding from between ommatidia, surface with middle 0.50 striate (with 7– setal length £3X width of ommatidium. 10 striae), finely granulate, lower 0.25 Ocelli large, prominent (Fig. 22). Median coarsely granulate (Fig. 47). Inter- ocellus circular, lateral ocelli slightly foveolar spaces on head finely striate ovate (Fig. 22). Clypeus projecting, cari- when piligerous foveolae are large. Re- nal teeth stout and sharp, carinae well maining integument smooth and pol- defined, less so dorsally, slightly divergent ished. Two color varieties exist. Dark ventrally, edge of clypeus between carinae form brown with katepisternum, meta- with shallow concave depression, de- soma and medial area of legs dark pression deepest between carinal teeth brown. Light form orange to yellow or- (Fig. 22). Paracarinal teeth poorly defined ange, except vertex and T2-4, T1 later- to absent (Fig. 22). Median clypeal tooth ally and apically and sternites apically usually well developed; sometimes less dark brown. Light form also with pos- developed (Fig. 22). Approximately 0.50 terior margin of orange maculation of T1 of eye dorsal to midpoint of head (Fig. 22). distinct. Both color forms with dark Mesosoma. Parapsidal lines present brown maculations anteriorly on prono- on posterior half of disk (Fig. 21). tum, anteromedian area of mesonotum, Mesonotum with indistinct to distinct area around parapsidal lines, sometimes median furrow, usually on posterior on median area of axillae, anteromedian 0.25–0.33 of disk. Propodeum some- and triangular posteromedian area of times with median longitudinal de- scutellum, medially on anepisternum, pression. Median bidentate process and medially and laterally on propo- present on metasternum. Wing venation deum (Fig. 52). Internal margins of as in Fig. 92. ocelli dark brown. Median frontal streak Metasoma. Lateral faces of post- present (as in Fig 50). Wings hyaline petiole weakly concave to straight sided. with pale yellow to hyaline veins. Petiolar spiracle tuberculate in some Morphometric Measurements.L cases. Postpetiolar spiracle usually not ;7.8–8.4, HW 1.35–1.60, VW 0.89– tuberculate. 1.01, HL 1.20–1.35, EL 0.40–0.51, OD Coloration, Sculpturing, and Pilosity. 0.10–0.15, OOD 0.15–0.20, LOW 0.10– Piligerous foveolae moderate to small, 0.12, MOW 0.10–0.12, CD 0.15–0.20, sparse, width 0.01–0.03 mm in diameter MFC 0.18–0.23, EW 0.30–0.35, SL on head, smaller on meso- and meta- 0.90–1.10, PDL 0.15–0.20, LF1 0.10– soma. Pubescence golden and erect, 0.12, LF2 0.08–0.11, LF3 0.08–0.10, longer and denser on head than else- WF1 0.06–0.08, FL 1.10–1.21, where, longest on anterior edge of FW 0.21–0.31, MW 1.30–1.40, DLM 342 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

2.49–2.62, PRH 1.00–1.11, PL 0.59– Color red brown to dark brown. Mandi- 0.75, PND 0.55–0.65, PH 0.60–0.72, ble brown anteriorly changing to yellow PPL 0.30–0.40, DPW 0.61–0.82, PPW brown at apex. Flagellum yellow brown 0.59–0.73, PHB 0.41–0.50, N=5. and legs segments brown medially Male.—Head. Eyes sometimes with grading to yellow towards base and 3–4 setae protruding from between om- apex. matidia, setal length £3X width of om- Morphometric Measurements.L matidium. Ocelli large and prominent, ;5.6–6.0, HW 1.00–1.10, VW 0.30– median ocellus circular, lateral ocelli 0.55, HL 0.81–0.92, EL 0.40–0.51, OD elliptical (Fig. 57). In lateral view, 0.10–0.15, OOD 0.15–0.20, LOW 0.11– clypeus with blunt, central lobe with 0.14, MOW 0.11–0.15, CD 0.15–0.25, indistinct anterior transverse carina. MFC 0.15–0.21, EW 0.32–0.40, SL Mesosoma. Propodeum rounded, de- 0.15–0.20, SW 0.10–0.15, PDL 0.05– clivous face perpendicular, flat except 0.10, PEW 0.11–0.15, LF1 0.20–0.25, with distinct to indistinct median longi- LF2 0.13–0.16, LF3 0.16–0.22, WF1 tudinal depression, basal face strongly 0.08–0.10, FL 1.09–1.22, FW 0.20–0.30, convex transversely and longitudinally MW 1.35–1.50, DLM 2.30–2.51, PRH (Fig. 56). Metapleuron broad almost 0.90–1.00, PL 0.60–0.75, PND 0.50– 0.66 as wide as high (Fig. 56). Wing 0.65, PH 0.39–0.52, PPL 0.29–0.41, venation as in Fig. 93. DPW 0.60–0.71, PPW 0.55–0.75, PHB Metasoma. In cephalic view, dorsum 0.18–0.30, N=6. of node transverse to having weak median Fourth instar worker larva.—Head. depression and weakly bilobate. Petiolar Large, subpyriform in anterior view and postpetiolar spiracles slightly tuber- (height 0.44 mm, width 0.51 mm) (Figs. culate to not tuberculate. Genitalia as in 152, 157). Cranium slightly broader than Fig. 74. long (Figs. 152, 157). Antenna with 2 or Coloration, Sculpturing, and Pilosity. 3 sensilla, each bearing spinule (Figs. Pubescence sparse, yellow to yellow 152, 157). Occipital setal row with 8–12 orange, erect to suberect, not of uniform bifid setae, base 0.5 to 0.8X total length length over body (0.10–0.35 mm long), of seta, 0.067–0.010 mm long (Figs. 152, longer on gena and vertex. Mesonotal 157). First setal row on vertex with 1–2 pubescence dense (Fig. 73). Base of bifid setae, base ;0.66X total length of propodeum striato-granulate. Propo- seta, 0.07–0.09 mm long (Figs. 152, deum with anteromedial area glabrous. 157). Second setal row on vertex with 4 Area between eye and insertion of an- simple setae, 0.13 mm long. Setae ventral tenna (Fig. 57), and lateral faces of to antenna level simple, 0.15–0.21 mm scutellum finely striate. Area between long (Figs. 152, 157). Clypeus with ocelli granulate. Remainder of head transverse row of 4 setae, inner setae weakly to coarsely granulate throughout, shorter than outer setae, 0.07–0.12 mm shagreened in some cases (Fig. 57). long (Figs. 152, 157). Labrum small, Lower surface of petiolar nodes coarsely short (breadth 2X length) (Fig. 152). La- striato-granulate, dorsum finely striato- brum with 4–6 minute sensilla and 2 setae granulate. Postpetiole often with fine on dorsal surface of each half and apical striations present dorsomedially. Meta- margin with 5–6 sensilla on each half. pleuron with dorsal longitudinal region Each half of epipharynx with 2–4 isolated finely striate. Gena granulate. Remain- sensilla. Straight medial portion of man- ing integument smooth and polished. dible with 2–5 teeth that decrease in size VOLUME 120, NUMBER 2 343 dorsally (Fig. 154). Maxilla with apex and S. metallica in both coloration and conical, palpus peg-like with 5 sensilla, sculpture of the head. Both S. pythia and each bearing one spinule. Galea conical S. metallica have other derived charac- with 2 apical sensilla, each bearing one ters, however, and thus are easily dis- spinule. Labium with patch of spinules tinguished from S. interrupta. dorsal to each palpus, spinules in short rows The gynes of S. interrupta and S. richteri of 2–3. Labial palpus slightly elevated with are similar in coloration and both some- 5sensilla,eachbearingonespinule. times have a distinct orange tergal macu- Body. Spiracles small, first spiracle lation with a demarcated posterior margin. larger than others. Body setae of 2 types. In many cases, the gynes of these two Simple setae (0.05–0.11 mm long) ar- species are difficult to differentiate, but ranged in transverse row of 5–10 on they may be separated by the sculpture of ventral surface of each thoracic somite the postpetiole. The gynes of S. interrupta and on each of 3 anterior abdominal are typically slightly lighter in coloration. somites, some with short denticulate In addition, the OOI of S. interrupta gynes tips. Bifid setae (0.07–0.10 mm long) is much greater than that of the S. richteri occur elsewhere, base 0.5–0.75X length gynes. The workers of these species, how- (Fig. 153). Some bifid setae on thoracic ever, are relatively easy to separate from the dorsum with base 0.33X length of seta. other members of this species-group. Length. 3.2–3.4 mm. The male is dark in coloration as are Material examined.—Various speci- males of most species in this group. The mens (FSCA). Also, see Appendix A. pubescence of the males is longer and Distribution.—There is some ques- denser than that of S. saevissima males. tion concerning the exact type locality Often, the head of the male is shagreened for S. interrupta. Santschi (1916) merely as it is in S. invicta males. lists the type locality as “Argentine: Bajo The larvae of S. interrupta are similar Hondo, Monte Hermeso”. But there are to those of S. invicta and S. saevissima. at least two locations in Argentina called They differ, however, in the size and Bajo Hondo. Buren (1972) placed the shape of the body setae. Also, the setae type locality in Buenos Aires Province ventral to the antennal level are typically and he considered the nominal S. inter- longer in S. interrupta than in S. invicta rupta range to span Uruguay and Buenos or S. saevissima. Aires, Entre Rios, Santa Fe Provinces, Argentina. He excluded the northwest- ern Argentinian and Bolivian forms from Solenopsis invicta Buren the species. Trager (1991) placed the (Figs. 23, 24, 42, 58, 59, 75, 94, 95, 134, type locality in La Rioja Province, since 135, 167, 160–164) he considered Buenos Aires to be well outside the range of his concept of the Solenopsis saevissima var. wagneri species (Cordoba and Mendoza Prov- Santschi 1916: 380. [Syntype workers. inces in Argentina northward into ARGENTINA. Santiago de Estero. Bolivia (Fig. 202)) and he considered Near Icano. Wagner. NHMB.] (Name Santschi’s description to fit well within suppressed in accord with ICZN 1976 his image of S. interrupta. Here, we (2001) as proposed by Shattuck, Porter, follow Trager’s (1991) interpretation. and Wojcik (1999).) Comments.—The gynes of S. inter- S. saevissima saevissima cline S. saevissima rupta superficially resemble S. pythia richteri:Wilson1952:65.[MCZ.] 344 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

S. invicta Buren 1972: 9. Worker, gyne, Mesosoma. Parapsidal lines present male. [NMNH.] (Name conserved on posterior 0.50 of disk (Fig. 23). (ICZN 2001)). Mesonotum with indistinct, median fur- row on posterior one-sixth or less. Worker.—Head subquadrate to weakly Bidentate median process present on cordate (Fig. 135). Head of largest speci- metasternum (Fig. 23). Wing venation as mens cordate. Sculpture of head and in Fig. 94. mesosomal dorsum with small piligerous Metasoma. Lateral faces of post- foveolae, <0.01 mm in diameter. Median petiole slightly concave to wider ven- frontal streak present. Median ocellus in trally. Petiolar and postpetiolar spiracles largest major workers absent (Fig. 135). slightly tuberculate to not tuberculate. Mandibular costulae absent medially, dis- Coloration, Sculpturing, and Pilosity. tinct apically and basally along outer Piligerous foveolae small, sparse, width border. Mesonotum with 20–25 setae. <0.01 mm in diameter, larger on head Mesonotum with anteromedian margin in than on thorax and abdomen. Pubes- largest major workers gently curved. cence simple, golden and erect, longer Mesonotum in lateral view convex and denser on head than elsewhere, (Fig. 134). Propodeum sculpture glabrous longest on anterior edge of clypeus. posteroventral to spiracle (Fig. 134). Mesosoma with longest pubescence Postpetiole shape in posterior view width (length £0.25 mm) 2X longer than greater than height. Postpetiole in poste- shortest pubescence (Fig. 23). Mandible rior view with lower 0.66 or greater with 9–11 fine, distinct, costulae, some- transversely rugose to punctate-rugose, times costulae obsolescent medially. extreme dorsum nitid, granulate. Color Propodeum with fine striae throughout generally with head and mesosoma yellow (Fig. 23). Petiolar nodes with lower 0.75 red to dark red brown, gaster brown, T1 finely striate; granulate throughout. with maculation yellow red to concolorous Postpetiole usually with 12–18 stria- with surrounding integument. tions, often transverse (Fig. 41), other Gyne.—Head. Slightly broader than times appearing to create swirling or long, quadrate, wider dorsal to eyes than circular patterns. Remaining integument ventral to them, sides of head convex from smooth and polished. Color varies from eyes to occipital angles, straight to nearly red brown to brown red on dorsum of straight ventral to eyes (Fig. 24). Eyes head, dorsum of thorax, and katepis- sometimes with 2–10 setae protruding ternum of mesopleuron. Gaster brown. from between ommatidia, setal length Sometimes on lighter colored individuals, £3X width of ommatidium. Median ocel- bases of T1 and S1 are somewhat orange lus large, prominent, circular (Fig. 24). blending to brown apically. Brown macu- Lateral ocelli moderate to large, slightly lations sometimes present anteromedially ovate (Fig. 24). Clypeus projecting, carinal and on parapsidal lines (as in Fig. 52). teeth stout and sharp, carinae well defined, Median streak present (as in Fig. 50), less so dorsally, slightly divergent ven- weak, sometimes indistinct or absent. In- trally (Fig. 24). Paracarinal teeth small, ternal margins of ocelli often dark brown. sometimes poorly defined. Median clypeal Morphometric Measurements. L tooth well developed (Fig. 24). Approxi- ;5.9–8.3, HW 1.30–1.46, VW 0.66– mately 0.50 of eye dorsal to midpoint of 0.88, HL 1.18–1.43, EL 0.38–0.49, OD head (Fig. 24). Antennal scape in repose 0.10–0.18, OOD 0.19–0.26, LOW 0.08– surpasses lateral ocellus. 0.15, MOW 0.16–0.24, CD 0.15–0.22, VOLUME 120, NUMBER 2 345

MFC 0.15–0.25, EW 0.25–0.48, SL brown to black with antenna completely 0.78–1.11, PDL 0.13–0.25, LF1 0.08– yellow, sometimes scape and pedicel 0.14, LF2 0.07–0.10, LF3 0.07–0.12, brown. Mandibles brown to light brown. WF1 0.06–0.11, FL 0.94–1.26, FW Morphometric Measurements. L 0.22–0.36, MW 1.14–1.48, DLM 2.42– ;5.4–6.3, HW 0.91–1.08, VW 0.30– 2.73, PRH 0.88–1.19, PL 0.72–0.83, 0.40, HL 0.67–0.83, EL 0.37–0.53, OD PND 0.56–0.84, PH 0.57–0.78, PPL 0.06–0.11, OOD 0.18–0.26, LOW 0.09– 0.24–0.42, DPW 0.51–0.74, PPW 0.71– 0.18, MOW 0.10–0.17, CD 0.16–0.24, 0.77, PHB 0.26–0.48, N=25. MFC 0.13–0.18, EW 0.28–0.39, SL Male.—Head. Eyes sometimes with 0.16–0.20, SW 0.09–0.14, PDL 0.06– 2–10 setae protruding from between 0.10, PEW 0.10–0.15, LF1 0.10–0.17, ommatidia, setal length £3X width of LF2 0.13–0.15, LF3 0.12–0.16, WF1 ommatidium. Ocelli large and prom- 0.07–0.10, FL 1.00–1.15, FW 0.15–0.20, inent, elliptical (Fig. 59). MW 1.20–1.68, DLM 2.27–2.64, PRH Mesosoma. Propodeum rounded, de- 0.78–1.04, PL 0.62–0.69, PND 0.54– clivous face perpendicular, flat except 0.61, PH 0.44–0.56, PPL 0.20–0.28, with distinct to indistinct median longi- DPW 0.55–0.71, PPW 0.58–0.69, PHB tudinal depression, basal face strongly 0.14–0.28, N=25. convex transversely and longitudinally. Fourth instar worker larva.—Head. Metapleuron not broad, ;0.33 as wide Large, subpyriform in anterior view as high, sometimes with transverse pos- (height 0.50 mm, width 0.54 mm) (Figs. terior carina (Fig. 58). Wing venation as 160, 162). Cranium slightly wider than in Fig. 95. long (Figs. 160, 162). Antenna with 2 Metasoma. In cephalic view, dorsum or 3 sensilla, each with 1 spinule. In- of node with shallow to deep median tegument of head with minute spinules. impression and weakly to strongly bilo- Occipital setal row normally with 6–8 bate. Petiolar and postpetiolar spiracles bifid setae, base ;0.66X total length of distinctly tuberculate to not tuberculate. seta, setae 0.08–0.10 mm long (Figs. Genitalia Fig. 75. 160, 162). First setal row on vertex with Coloration, Sculpturing, and Pilosity. 2 bifid setae, base ;0.66X total length of Pubescence short, sparse, yellow to brown, seta, 0.05–0.07 mm long (Figs. 160, erect to suberect (0.20–0.30 mm), longest 162). Second setal row on vertex with on gena and vertex. Mesonotal pubes- 4–6 simple setae, ;0.10 mm long (Figs. cence dense (as in Fig. 73). Propodeum 160, 162). Setae anterior to antenna level with base striato-granulate, medially finely simple, 0.08–0.14 mm long (Figs. 160, granulate (Fig. 58). Area between eye and 162). Clypeus with transverse row of 4 insertion of antenna, posterior portion of setae, inner setae shorter than outer se- metapleuron, lateral faces of scutellum, and tae, 0.06–0.08 mm long (Figs. 160, 162). base of petiolar node granulate to striato- Labrum small, short (width 2.5X granulate (Fig. 58). Posterior surface of length). Labrum with 4–6 minute sen- postpetiolar node granulate throughout, silla and 2 setae on dorsal surface of rugae present dorsomedially. Area between each half and apex with 4–6 sensilla on ocelli weakly to coarsely striato-granulate each half. Each half of the epipharynx (Fig. 58). Gena coarsely rugose to coarsely with 2–3 isolated and 2 contiguous sen- striato-granulate. Head often completely silla. Straight medial portion of mandi- granulate, shagreened, dull. Remaining in- ble with 2–5 teeth that decrease in size tegument smooth and polished. Color red dorsally (Fig. 160). Maxilla with apex 346 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON conical, palpus peg-like with 5 sensilla, Comments.—Although it was dis- each bearing one spinule (Fig. 160). covered that the name S. wagneri has Galea conical with 2 apical sensilla priority over S. invicta (Bolton 1995), bearing spinules (Fig. 160). Maxilla with the International Commission of Zoo- sclerotized band between cardo and sti- logical Nomenclature ruled that the pes. Labium with patches of spinules name S. invicta is to be conserved in dorsal to each palpus, in 2–3 rows. La- order to maintain stability and continuity bial palpus slightly elevated with 5 sen- (ICZN 2001). silla, each bearing one spinule. As noted with the workers (Trager Body. Stout. Spiracles small, first 1991; J. Pitts and K. R. Ross, pers. obs.), spiracle larger than others. Body setae of the gynes are highly variable in color. 2 types. Simple setae (0.06–0.11 mm The darker variants of gynes are found in long) arranged in transverse row of 6–12 southeastern Brazil to Uruguay and Ar- on ventral surface of each thoracic so- gentina and are associated with the mite and on each of 3 anterior abdominal darker workers. A lighter variant occurs somites, some with short denticulate in the northern area of the species’ range. tips. Bifid setae (0.06–0.09 mm long) The gynes and workers of these colonies occur elsewhere, base ;0.5X length are also similar in coloration. A third (Fig. 161). variant, a light orange form, is found in Length. About 3.1 mm (Fig. 164). the Pantanal region of Brazil. This form Material examined.—Various speci- has larger workers and gynes. No mor- mens (FSCA). Also, see Appendices A phological differences could be found and B. between these forms, other than size and Distribution.—The range of Sol- coloration. enopsis invicta in South America cur- The darker colored gynes of S. invicta rently extends from as far north as Porto look most similar to S. megergates and S. Velho, Rondoˆnia State, Brazil and east- quinquecuspis. However, the CI and OI ward from Peru and Bolivia to Cuiaba´, of S. invicta gynes are normally smaller Mato Grosso State, Brazil, southward to than those of S. megergates and the OI Santiago del Estero Province of Argen- of S. invicta is normally smaller than that tina, through Uruguay to Sa˜o Paulo of S. quinquecuspis. The lighter gynes of State, Brazil (Fig. 203). Its range in S. invicta look similar to S. richteri and North America includes the Gulf States S. interrupta. The gynes of S. interrupta west to Texas. It is found sporadically in normally are lighter in coloration than New Mexico and Arizona and apparently S. invicta, have larger cephalic foveolae, is well established in California. It re- and sometimes have distinct striations cently has been introduced to Australia, between the foveolae. The OOI of Taiwan, China, and Japan (Henshaw et al. S. invicta gynes is normally greater than 2005; Ascunce et al. 2011). A compre- that of S. richteri, and the postpetiole of hensive assessment of genetic variation S. invicta gynes has straight sides, unlike for colonies sampled from 75 geographic the concave sides of S. richteri. In many sites worldwide revealed that at least nine cases, the sculpture of the mandible and separate introductions of S. invicta oc- postpetiole can help separate S. invicta curred into newly invaded areas and that gynes from similar species. The gynes the main southern U.S. population is of S. invicta normally have the most probably the source of these secondary densely sculptured postpetiole compared introductions (Ascunce et al. 2011). to the other species. VOLUME 120, NUMBER 2 347

The male of S. invicta is dark in col- 6 sensilla on each half. Each half of oration and is similar to most of the other posterior surface of labrum with 2–3 darker species. The pubescence of the isolated sensilla. Straight medial portion S. invicta male is longer and denser than of mandible with 2–5 teeth that decrease that of S. saevissima. Sometimes the in size basally. Maxilla with apex coni- head of the S. invicta male is shagreened cal, palpus peg-like with 5 sensilla, each as in S. interrupta. The gena of the male bears one spinule. Galea conical with 2 is much more sculptured than in other apical sensilla. Labium with patch of species. In moderate to extreme forms, spinules dorsal to each palpus, spinules this feature is easily recognized and it coarse and isolated or in short rows of may be autapomorphic for S. invicta. 2–3. Labial palpus slightly elevated with Allozyme, microsatellite, and mito- 5 sensilla, each bearing one spinule. chondrial DNA data suggest that the Body. Spiracles small, first spiracle current concept of S. invicta might ac- larger than others. Body setae of 2 types. tually represent a group of several Simple setae (0.07–0.12 mm long) ar- cryptic species (Ross and Shoemaker ranged in transverse rows of 6–9 on 2005; Shoemaker et al. 2006; Ross et al. ventral surface of each thoracic somite 2007). A thorough examination of S. and on each of 3 anterior abdominal invicta adults from genetically distinct somites, some with short denticulate populations revealed no apparent mor- tips. Bifid setae (0.08–0.12 mm long) phological differences. In one colony of occur elsewhere, base ;0.33X length, S. invicta (colony O-18, see Appendix branches more or less perpendicular to A), the larvae differed from typical S. base, tips recurved. invicta both in size and setal type. This Length. 2.7–2.9 mm. colony was collected in close proximity to typical S. invicta and the adults do not differ from typical S. invicta. Solenopsis macdonaghi Santschi Fourth instar worker larva (O-18).— (Figs. 25, 26, 60, 61, 76, 77, 96, 97, 136, Head. Large, subpyriform in anterior 137, 165–169) view. Cranium slightly broader than long. Antenna with 2 or 3 sensilla, each bearing Solenopsis saevissima var. macdonaghi spinule. Integument of head with minute Santschi 1916: 379. [Syntype workers, spinules. Occipital setal row with 4–6 gynes. ARGENTINA. Entre Rios. setae (0.06–0.08 mm long), median pair Estacio´n Sosa. MacDonagh. NHMB.] simple, other setae bifid with base 0.66– S. geminata pylades: Bruch 1916: 313. 0.75X total length of seta. First setal row S. (Solenopsis) saevissima interrupta: on vertex with 2 simple setae, ;0.09 mm Creighton 1930: 89. long. Second setal row on vertex with S. macdonaghi: Trager 1991: 179. 2 simple setae, 0.10–0.12 mm long. Se- tae ventral to antenna level simple, 0.09– Worker.—Head broad, cordate (Fig. 0.12 mm long. Clypeus with transverse 137). Head sculpture with small piligerous row of 4 setae, inner setae shorter than foveolae, approximately 0.01 mm in di- outer setae, 0.05–0.10 mm long. Labrum ameter. Median frontal streak absent. small, short (width 1.8X length), slightly Median ocellus in largest major workers narrowed medially. Labrum with 5 min- present. Mandibular costulae obsoles- ute sensilla and 2 setae on anterior sur- cent, except apically, rarely complete. face of each half and ventral border with Mesonotum with 20–25 setae (Fig. 136). 348 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Promesonotal suture in largest major Coloration, Sculpturing, and Pilosity. workers angulate medially, sometimes Piligerous foveolae small, sparse, width projecting upward (Fig. 136). Meso- <0.01 mm in diameter. Pubescence notum in lateral view weakly convex. simple, golden and erect, longer and Propodeum sculpture glabrous poster- denser on head than elsewhere, longest on oventral to spiracle (Fig. 136). Propo- anterior edge of clypeus. Mesosoma with deum in largest major workers curves longest pubescence (length >0.30 mm) upward from metanotal groove higher 3X longer than shortest pubescence than flattened posterior portion, appear- (Fig. 25). Mandible with 10–12 fine, ing as anterior raised portion in lateral distinct costulae present throughout. view. Postpetiole shape much broader Propodeum with fine striae throughout than high. Postpetiole in posterior view (Fig. 25). Petiolar node with lower 0.75 of lacking transverse rugae or with rugae surface finely striate, dorsum polished. medially, normally granulate to dorsum. Postpetiole node with striations on lower Color generally red yellow to brown 0.75 of surface somewhat coarser, 7–9 yellow, gaster dark brown, T1 with red striae, finely granulate, dorsum polished yellow to brown yellow maculation. (Fig. 41). Remaining integument smooth Gyne.—Head. Slightly wider than and polished. Color varies from orange to long, quadrate, sides of head convex dark orange and legs orange to yellow from eyes to occipital angles, straight to orange with T1-T4 brown laterally and nearly straight ventral to eyes (Fig. 26). apically. Basal orange coloration of T1 Eyes sometimes with 3–4 setae pro- blends evenly to brown apically. Meso- truding from between ommatidia, setal notum maculations absent on parapsidal length £3X width of ommatidium. Ocelli lines, although sometimes present ante- large, prominent (Fig. 26). Median romedially. Internal margins of ocelli not ocellus circular, lateral ocelli slightly dark brown. Median frontal streak absent. ovate (Fig. 26). Clypeus projecting, Morphometric Measurements. L carinal teeth stout and sharp, carinae ;6.9–7.5, HW 1.42–1.46, VW 0.85– well defined, slightly divergent ventrally, 0.92, HL 1.22–1.34, EL 0.41–0.46, OD edge of clypeus between carinae with 0.12–0.15, OOD 0.23–0.25, LOW 0.08– shallow concave depression, depression 0.11, MOW 0.10–0.14, CD 0.15–0.17, deepest between carinal teeth (Fig. 26). MFC 0.18–0.20, EW 0.30–0.34, SL Paracarinal teeth small, indistinct (Fig. 0.95–1.05, PDL 0.21–0.25, LF1 0.10– 26). Median clypeal tooth poorly 0.14, LF2 0.07–0.11, LF3 0.07–0.09, developed, usually absent (Fig. 26). WF1 0.07–0.09, FL 1.20–1.25, FW Approximately 0.50 of eye dorsal to 0.26–0.27, MW 1.35–1.45, DLM 2.48– midpoint of head (Fig. 26). 2.84, PRH 1.02–1.09, PL 0.73–0.82, Mesosoma. Parapsidal lines present on PND 0.54–0.70, PH 0.65–0.70, PPL posterior 0.50 of disk (Fig. 25). Meso- 0.32–0.38, DPW 0.65–0.70, PPW 0.70– notum with indistinct, median furrow 0.75, PHB 0.35–0.40, N=7. present on posterior 0.25 or less. Bi- Male.—Head. Eyes normally with 2–4 dentate median process present on meta- setae protruding from between ommatidia, sternum. Wing venation as in Fig. 96. setal length £3X width of ommatidium. Metasoma. Lateral faces of postpetiole Ocelli moderate to large, prominent, straight to weakly convex. Petiolar and elliptical (Fig. 61). postpetiolar spiracles tuberculate in some Mesosoma. Propodeum rounded, de- cases. clivous face perpendicular, flat except VOLUME 120, NUMBER 2 349 with distinct to indistinct median longi- PPL 0.25–0.34, DPW 0.50–0.74, PPW tudinal depression, basal face strongly 0.54–0.79, PHB 0.20–0.29, N=10. convex transversely and longitudinally. Fourth instar worker larva.—Head. Metapleuron not broad, ;0.66 as wide Large, subpyriform in anterior view as high (Fig. 60). Wing venation as in (height 0.47 mm, width 0.54 mm) (Figs. Fig. 97. 165, 169). Cranium slightly wider than Metasoma: In cephalic view, dorsum long. Antenna with 2 or 3 sensilla, each of node with deep median depression, bearing spinule (Figs. 165, 169). Oc- bilobate. Petiolar and postpetiolar spi- cipital setal row with 6–8 setae, median racles distinctly tuberculate to not tu- pair simple (Fig. 171) otherwise bifid, berculate. Genitalia as in Figs. 76 and base 0.5–0.66X total length of seta, 77. 0.06–0.10 mm long (Figs. 165, 169). Coloration, Sculpturing, and Pilosity. First setal row on vertex with 2 dentic- Pubescence short, thin, yellow, erect to ulate to simple setae, 0.10–0.11 mm suberect and of uniform length over long. Second setal row on vertex with 4 body (0.25–0.30 mm), longest on gena simple setae, 0.10–0.13 mm long (Figs. and vertex. Mesonotal pubescence dense 165, 169), rarely denticulate. Setae (as in Fig. 73). Propodeum with base ventral to antenna level simple, 0.12– striato-granulate, medially finely granu- 0.16 mm long (Figs. 165, 169). Clypeus late. Area between eye and insertion of with transverse row of 4 setae, inner antenna, pronotum posteriorly and base setae shorter than outer setae, 0.10–0.11 of petiolar node coarsely granulate. mm long (Figs. 165, 169). Labrum Posterior surface of postpetiolar node small, short (breadth 2X length). La- granulate throughout. Area between brum with 4–6 sensilla and 2 setae on ocelli and vertex finely striato-granulate dorsal surface of each half. Apex with to granulate (Fig. 61). Areas antero- 4–6 sensilla on each half. Each half of lateral to median ocellus usually gla- epipharynx with 2–3 isolated sensilla. brous (Fig. 61). Gena coarsely granulate, Straight medial portion of mandible with less often rugose anterior to occipital 2–5 teeth that decrease in size dorsally carina, never rugose throughout. Meta- (Fig. 168). Maxilla with apex conical, pleuron and lateral faces of scutellum palpus peg-like with 5 sensilla, 1 bears striato-granulate. Remaining integument spinule. Galea conical with 2 apical smooth and polished. Color red brown to sensilla bearing spinules. Labium with black, antennae and legs yellow brown. patch of spinules dorsal to each palpus, Mandibles yellow, extreme apex brown. spinules in rows of 2–3. Labial palpus Morphometric Measurements. L ;5.7– slightly elevated with 5 sensilla, each 6.6, HW 1.00–1.20, VW 0.34–0.39, HL bearing one spinule. 0.74–0.89, EL 0.40–0.52, OD 0.08–0.11, Body. Spiracles small, first spiracle OOD 0.15–0.28, LOW 0.10–0.18, MOW larger than others. Body setae of 2 types. 0.13–0.16, CD 0.16–0.22, MFC 0.13– Simple setae (0.06–0.12 mm long) ar- 0.18, EW 0.34–0.41, SL 0.14–0.18, SW ranged in transverse row of 6–10 on ven- 0.09–0.11, PDL 0.05–0.08, PEW 0.12– tral surface of each thoracic somite and on 0.15, LF1 0.20–0.24, LF2 0.12–0.15, LF3 each of 3 anterior abdominal somites, 0.14–0.18, WF1 0.07–0.10, FL 0.95–1.30, some with short denticulate tips. Bifid se- FW 0.15–0.22, MW 1.35–1.62, DLM tae (0.09–0.14 mm long)occurelsewhere, 2.28–2.80, PRH 0.80–1.10, PL 0.55– base 0.66X length (Fig. 166). Bifid setae 0.65, PND 0.50–0.60, PH 0.43–0.63, on thoracic dorsum with shorter bases. 350 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Length. 3.4–3.5 mm. bifid setae on the head capsule. The larva Material examined.—Various speci- of S. macdonaghi is virtually in- mens (FSCA). Also, see Appendix A. distinguishable from that of S. me- Distribution.—Solenopsis macdon- gergates and S. quinquecuspis, despite aghi is found throughout the floodplains the smaller body size and the longer base of eastern Argentina and western Ur- of the body setae in S. macdonaghi. uguay (Fig. 202). Several records exist for Paraguay. Trager (1991) reports a Solenopsis megergates Trager population at Cochabamba, Bolivia but this is far removed from the known range (Figs. 27, 28, 62, 63, 78, 79, 98, 99, 138, of S. macdonaghi and, in fact, may rep- 139, 170–175) resent an introduction. Solenopsis megergates Trager 1991: Comments.—Superficially, the lighter 181–182. [Holotype worker. BRAZIL. gynes of S. macdonaghi look most similar Parana´ State. 4 km North of Curitiba. to S. interrupta and S. metallica in color- Trager. MZSP.] ation. However, the coloration does differ by being a somewhat duller yellow orange Worker.—Head broad, cordate (Fig. in S. macdonaghi.Also,theS. macdon- 139). Head sculpture with small pilig- aghi gynes lack the large piligerous fo- erous foveolae, approximately 0.01 mm veolae on the head and mesosoma, along in diameter. Median frontal streak absent with interfoveolar striae, which are char- or faint. Median ocellus in largest major acters present in S. interrupta and S. met- workers present (absent in Fig. 139). allica. The gynes of these three species Mandibular costulae usually present also differ slightly to greatly in sculpturing throughout, sometimes obsolescent. Meso- of the postpetiole and can be normally notum with 20–25 setae (Fig. 138). Meso- distinguished by this character. notum weakly convex, in lateral view (Fig. Trager (1991) reported that the heads 138). Promesonotal suture in largest major of S. macdonaghi gynes are typically workers angulate, sometimes projecting broader than other species, but this obser- upward (Fig. 138). Propodeum sculpture vation was based on a limited number of glabrous posteroventral to spiracle (Fig. specimens. Additional measurements have 138). In largest major workers, propodeum shown this not to be the case (Table 5). curves directly to flattened posterior portion The males of S. macdonaghi closely (Fig. 138). Postpetiole shape much broader resemble other species, but they, along than high. Postpetiole in posterior view with S. saevissima, are among the largest transversely rugose on lower 0.50–0.75, males. The males of S. macdonaghi look weakly granulate, sculpture not extending to most similar to S. quinquecuspis in size, dorsum. Color red brown on head, meso- shape and coloration. Although males of soma, legs and T1 maculation. Color dark S. macdonaghi are normally less coarsely brown on metasoma excluding maculation. sculptured than S. quinquecuspis, the Gyne.—Head. Slightly broader than males of these two species are not easily long, quadrate, sides of head convex distinguished. Males of S. macdonaghi from eyes to occipital angles, straight to are also very similar to S. megergates,but nearly straight ventral to eyes (Fig. 28). the CI for males of S. macdonaghi is Eye sometimes with 3–4 setae pro- somewhat smaller than for S. megergates. truding from between ommatidia, length The larva of S. macdonaghi is distinct most setae <3X length of ommatidium, from that of S. saevissima in that it has sometimes setae longer, ;4X length of VOLUME 120, NUMBER 2 351 ommatidium. Ocelli large, prominent sometimes only slightly discernable from (Fig. 28). Median ocellus circular, lateral surrounding integument. Integument along ocelli slightly ovate (Fig. 28). Clypeus internal margins of ocelli usually brown. projecting, carinal teeth stout and sharp, Median frontal streak absent, sometimes carinae well defined, less so dorsally, area is slightly darker than surrounding slightly divergent ventrally (Fig. 28). integument. Paracarinal teeth small, sometimes Morphometric Measurements. L poorly defined (Fig. 28). Median clypeal ;7.4–8.9, HW 1.35–1.68, VW 0.90– tooth well developed, infrequently in- 1.02, HL 1.22–1.42, EL 0.40–0.48, OD distinct (Fig. 28). Approximately 0.50 of 0.14–0.20, OOD 0.20–0.28, LOW 0.10– eye dorsal to midpoint of head (Fig. 28). 0.12, MOW 0.10–0.12, CD 0.16–0.26, Mesosoma. Parapsidal lines present MFC 0.16–0.28, EW 0.30–0.42, SL on posterior 0.50 of disk (Fig. 27). 0.95–1.15, PDL 0.21–0.25, LF1 0.10– Mesonotum with indistinct, poster- 0.14, LF2 0.08–0.11, LF3 0.07–0.11, omedian furrow. Wing venation as in WF1 0.05–0.08, FL 1.15–1.32, FW Fig. 98. 0.25–0.30, MW 1.46–1.54, DLM 2.51– Metasoma. Lateral faces of postpetiole 2.82, PRH 0.90–1.25, PL 0.71–0.79, straight to weakly concave. Petiolar and PND 0.55–0.68, PH 0.65–0.75, PPL postpetiolar spiracles tuberculate in some 0.30–0.41, DPW 0.56–0.68, PPW 0.74– cases. 0.79, PHB 0.38–0.45, N=6. Coloration, Sculpturing, and Pilosity. Male.—Head. Eye normally with 3–4 Piligerous foveolae moderate, width setae protruding from between ommatidia, 0.005–0.03 mm in diameter, larger on setal length £3X width of ommatidium. head than on thorax and abdomen. Pu- Ocelli moderate to small, elliptical bescence simple, golden and erect, lon- (Fig. 63). ger and denser on head than elsewhere, Mesosoma. Propodeum rounded, de- longest on anterior edge of clypeus. clivous face perpendicular, flat except Mesosoma with longest pubescence with distinct to indistinct median longi- (length >0.30 mm) 2X longer than tudinal depression, basal face strongly shortest pubescence (Fig. 27). Some- convex transversely and longitudinally. times fine striae present between ocelli. Metapleuron not broad, ;0.33 as wide Mandible with 5–7 coarse, distinct cos- as high (Fig. 62). Wing venation as in tulae present, sometimes obsolescent Fig. 99. medially. Propodeum with fine striae Metasoma. In anterior view, dorsum of posteriorly, anterior 0.25 polished (Fig. node with deep median impression, bi- 27). Petiolar nodes with lower 0.50 of lobate. Petiolar and postpetiolar spiracles posterior surface finely striate to granu- distinctly tuberculate to not tuberculate. late, dorsum polished. Postpetiole with 12– Genitalia as in Figs. 78 and 79. 16 striations, dorsum finely granulate to Coloration, Sculpturing, and Pilosity. polished. Remaining integument smooth Pubescence short, thin, yellow, erect to and polished. Color varies from red brown suberect and of uniform length over to brown orange. Ocellar triangle some- body (0.25–0.30 mm), longest on gena times darkly pigmented. Legs usually red and vertex. Mesonotal pubescence dense brown, sometimes becoming lighter than (as in Fig. 73). Propodeum with base body (yellow brown). Mesonotal macu- striato-granulate (Fig. 62). Area between lations present anteromedially and para- eye and insertion of antenna (Fig. 63), psidal lines, usually black to dark brown, posterior portion of metapleuron, and 352 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON base of petiolar node granulate. Some- inner setae shorter than outer setae, times, base of petiolar node rugose to 0.06–0.10 mm long (Figs. 170, 173, striato-granulate. Area between ocelli 174). Labrum small, short (breadth ;2X (Fig. 63) and gena striato-granulate. Vertex length). Labrum with 4 sensilla and 2 granulate (Fig. 63). Areas anterolateral to setae on dorsal surface of each half and median ocellus usually glabrous (Fig. 63). apex with 6 sensilla on each half. Each Lower 0.25 of postpetiole finely striato- half of epipharynx with 3–5 isolated. granulate to granulate, remaining surface Straight medial portion of mandible with granulate. Lateral faces of scutellum gla- 2–5 teeth that decrease in size dorsally brous (Fig. 62). Remaining integument (Fig. 172). Maxilla with apex conical, smooth and polished. Color red brown to palpus peg-like with 5 sensilla, each brown, antennae and legs brown yellow. bearing one spinule. Galea conical with Mandibles yellow to yellow brown. 2 apical sensilla, each bearing one spi- Morphometric Measurements. L nule. Labium with patch of spinules ;5.0–6.7, HW 0.97–1.10, VW 0.30– dorsal to palpus, in short rows of 2–3. 0.38, HL 0.66–0.80, EL 0.40–0.49, OD Labial palpus slightly elevated with 5 0.06–0.09, OOD 0.12–0.18, LOW 0.09– sensilla, each bearing one spinule. 0.12, MOW 0.10–0.15, CD 0.15–0.18, Body. Spiracles small, first spiracle MFC 0.13–0.16, EW 0.30–0.38, SL larger than others. Integument with fine 0.16–0.18, SW 0.09–0.10, PDL 0.05– rugae throughout. Body setae of 2 types 0.06, PEW 0.10–0.15, LF1 0.14–0.21, (Fig. 175). Simple setae (0.04–0.14 mm LF2 0.10–0.15, LF3 0.13–0.16, WF1 long) arranged in transverse row of 6–10 0.06–0.09, FL 1.04–1.11, FW 0.16–0.21, on ventral surface of each thoracic so- MW 1.40–1.54, DLM 2.35–2.44, PRH mite and on each of 3 anterior abdominal 0.81–1.05, PL 0.61–0.66, PND 0.56– somites, some with short denticulate 0.61, PH 0.46–0.54, PPL 0.22–0.31, tips. Bifid setae (0.06–0.11 mm long) DPW 0.56–0.63, PPW 0.65–0.69, PHB occur elsewhere, base ;0.5X length 0.21–0.28, N=8. (Figs. 174, 175), some with bases Fourth instar worker larva.—Head. ;0.75X (0.08–0.10 mm long) on tho- Large, subpyriform in anterior view racic dorsum posterior to head capsule. (height 0.46 mm, width 0.50 mm) (Figs. Length. 3.7–3.8 mm. 170, 173). Cranium slightly broader than Material examined.—Various speci- long (Figs. 170, 173). Antenna with 2 or mens (FSCA). Also, see Appendix A. 3sensilla,eachbearingspinule(Figs.170, Distribution.—The type specimens 171, 173). Occipital setal row with 4–6 were unavailable for study. The type setae (0.06–0.08 mm long) (Figs. 170, series locality is Curitiba, Parana´, Brazil 173); inner and outer setae simple to (Trager 1991). Solenopsis megergates is denticulate, otherwise bifid, base ;0.75 currently known only from the three length of seta (Figs. 170, 173, 174). First southern Brazilian states of Parana´, setal row on vertex with 2 simple to Santa Catarina, and Rio Grande do Sul denticulate setae, 0.07–0.08 mm long (Fig. 202). (Figs. 170, 173, 174). Second setal row Comments.—Gynes and workers of on vertex with 4 simple setae, 0.09–0.13 S. megergates are similar in coloration. mm long (Figs. 170, 173, 174). Setae The workers of this species are the ventral to antenna level simple, 0.08– largest of any of the fire ants. The gynes, 0.14 mm long (Figs. 170, 173, 174). along with those of S. macdonaghi and Clypeus with transverse row of 4 setae, S. saevissima, are the largest gynes in VOLUME 120, NUMBER 2 353 this group. The darker-colored gynes of to spiracle (Fig. 140). Postpetiole shape as S. megergates could be confused with S. high as or higher than broad. Postpetiole invicta, but the CI and OI of S. me- sculpture in posterior view with lower 0.75 gergates are normally larger than those transversely rugose, granulate, weakly of S. invicta. In many cases, the sculp- granulate to glabrous and shiny. Color ture of the mandible and postpetiole for generally brown yellow to darker yellow workers can help separate S. megergates brown with brown gaster. from similar species. Gyne.—Head. Slightly broader than The males of S. megergates are dis- long, quadrate, sides of head convex tinct from all other species by lacking from eyes to occipital angles, straight sculpture on the lateral faces of the anterior to eyes (Fig. 30). Eye sometimes scutellum; the males of the other species with 6–10 long setae protruding from have weakly to strongly striate lateral between ommatidia, setal length >4X faces. Also, the males of S. megergates length of ommatidia. Ocelli large, prom- usually have smaller ocelli than their inent (Fig. 30). Median ocellus circular, closest relatives (Pitts et al. 2005), S. lateral ocelli slightly ovate (Fig. 30). macdonaghi and S. quinquecuspis. Ocelli placed in more anterior position on The larvae of S. megergates are dis- head (Fig. 30). Clypeus projecting, cari- tinct from the S. saevissima type by nal teeth stout and sharp, carinae well having simple setae on the head capsule. defined, prominent between antennal The larvae are virtually identical to scrobes, slightly divergent ventrally, edge S. macdonaghi and S. quinquecuspis. of clypeus between carinae with shallow The S. megergates larvae have bifid setae concave depression, depression deepest on the body that differ slightly from between carinal teeth (Fig. 30). Para- S. macdonaghi and S. quinquecuspis by carinal teeth small, well defined (Fig. 30). having a slightly longer base. Median clypeal tooth well developed (Fig. 30). Approximately 0.50 of eye Solenopsis pusillignis Trager dorsal to midpoint of head (Fig. 30). Mesosoma. Parapsidal lines present (Figs. 29, 30, 45, 64, 65, 80, 87, 88, 140, on posterior 0.50 of disk (Fig. 29). 141, 190–194) Mesonotum with median furrow on Solenopsis pusillignis Trager 1991: 194. posterior 0.25. Metasternum with bi- [Holotype worker. BRAZIL. Mato dentate median process. Wing venation Grosso State. Cuiaba´. Trager. MZSP.] as in Fig. 87. Metasoma. Lateral faces of post- Worker.—Head subovate to cordate petiole weakly to strongly concave. In (Fig. 141). Head sculpture with small lateral view, petiolar node obtusely tri- piligerous foveolae, <0.01 mm in di- angular, profile of peduncle flattened an- ameter. Median frontal streak absent. teriorly, convex posteriorly. Postpetiole Median ocellus in largest major workers evenly convex. Postpetiolar spiracles absent. Mandibular costulae well de- weakly tuberculate. veloped throughout entire length at least Coloration, Sculpturing, and Pilosity. medially. Mesonotum with 20–25 setae Piligerous foveolae small, sparse, width (Fig. 140). Promesonotal suture in largest <0.01 mm in diameter, larger on head major workers gently curved medially, than on thorax and abdomen. Pubes- never projecting upward (Fig. 140). Pro- cence simple, golden and erect, longer podeum sculpture granulate posteroventral and denser on head than elsewhere, 354 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON longest on anterior edge of clypeus. dense, yellow, erect to suberect and of Mesonotum pubescence 0.06–0.25 mm, uniform length over mesonotum, longest longest pubescence on mesonotum 3–4X on gena and vertex. Mesonotal pubes- longer than shortest pubescence (Fig. cence sparse (as in Fig. 72). Propodeum 29). Mandible with 9–11 fine, distinct striato-granulate, medially finely granu- costulae present throughout. Propodeum late (Fig. 64). Lateral faces of scutellum with fine striae throughout (Fig. 29). striato-granulate (Fig. 64). Surface Petiolar node basal 0.75 with striato- granulate in area between eye and in- granulate, dorsum polished. Posterior sertion of antenna (Fig. 65), posterior face of postpetiolar node with lower portion of metapleuron, and base of 0.50–0.75 finely striate, lower 0.75 petiolar node. Posterior surface of post- granulate, dorsum polished (Fig. 45). petiolar node with lower 0.25 finely Remaining integument smooth and pol- striato-granulate, sometimes with lower ished. Color generally orange with 0.50 finely striato-granulate but glabrous mandibles and antennae orange brown, medially, dorsum polished. Area be- apical and lateral margins of metasoma tween ocelli rugose to granulate (Fig. segments 3–6 brown, and internal mar- 65). Vertex glabrous posterior to ocelli. gins of ocelli dark brown. Several striae present anterior to occipi- Morphometric Measurements. L tal carina. Area posterior to eyes and ;6.6, HW 1.20, VW 0.80, HL 1.14, EL antennal scrobes weakly granulate. Re- 0.29, OD 0.12, OOD 0.16, LOW 0.11, maining integument smooth and pol- MOW 0.13, CD 0.13, MFC 0.16, EW ished. Head and gaster red brown. 0.28, SL 0.83, PDL 0.17, LF1 0.09, LF2 Clypeus, mandibles, petiole and post- 0.07, LF3 0.08, WF1 0.06, FL 0.96, FW petiole lighter yellow. Antennae and legs 0.23, MW 1.25, DLM 2.20, PRH 0.43, yellow. Mesosoma yellow to brown with PL 0.61, PND 0.51, PH 0.60, PPL 0.34, median longitudinal stripe, area around DPW 0.50, PPW 0.62, PHB 0.36, N=1. parapsidal lines and scutellum red Male.—Head. Eye normally with 3–4 brown. Sometimes mesosoma yellow setae protruding from between omma- and parapsidal lines only slightly darker tidia, setal length £3X width of omma- than surround integument. tidium. Ocelli very large and prominent, Morphometric Measurements. L elliptical (Fig. 65). ;4.9–5.4, HW 0.95–1.0, VW 0.35–0.42, Mesosoma. Propodeum rounded, de- HL 0.74–0.80, EL 0.44–0.48, OD 0.10– clivous face perpendicular, flat except 0.14, OOD 0.10–0.13, LOW 0.16–0.17, with distinct to indistinct median longi- MOW 0.16–0.19, CD 0.10–0.12, MFC tudinal depression, basal face strongly 0.33–0.36, EW 0.3–0.40, SL 0.14–0.18, convex transversely and longitudinally. SW 0.07–0.10, PDL 0.05–0.08, PEW Metapleuron not broad, ;0.50 as wide 0.10–0.12, LF1 0.17–0.19, LF2 0.13– as high (Fig. 64). Wing venation as in 0.15, LF3 0.13–0.14, WF1 0.09–0.10, Fig. 88. FL 0.98–1.05, FW 0.15–0.19, MW 1.20– Metasoma. In cephalic view, dorsum 1.30, DLM 2.15–2.30, PRH 0.80–0.88, of node with shallow median impression, PL 0.65–0.66, PND 0.58–0.61, PH 0.40– weakly bilobate. Petiolar and postpetiolar 0.42, PPL 0.26–0.30, DPW 0.49–0.55, spiracles distinctly tuberculate to not tu- PPW 0.55–0.64, PHB 0.14–0.16, N=8. berculate. Genitalia as in Fig. 80. Fourth instar worker larva.—Head. Coloration, Sculpturing, and Pilosity. Large, subpyriform in anterior view Pubescence short (0.15–0.20 mm), (height 0.44 mm, length 0.44 mm) (Figs. VOLUME 120, NUMBER 2 355

190, 193). Cranium as broad as long Length. 2.6–2.7 mm. (Figs. 190, 193). Antenna with 2 or 3 Material examined.—See Appendix A. sensilla, each bears spinule (Figs. 190, (Holotype was unavailable for study.) 193). Occipital setal row with 10–12 Distribution.—Currently, S. pusillignis bifid setae (less often 8), base ;0.3– is known from the type locality and the 0.5X total length of seta (Fig. 191), setae vicinity of Corumba´, Mato Grosso do 0.05–0.10 mm long (Figs. 190, 193, Sul, Brazil (Fig. 203). 194). First setal row on vertex with 2 Variation.—Trager (1991) considered bifid setae, base ;0.5X total length of this to be a small species, but also re- seta, ;0.07 mm long (Figs. 190, 193, ported measurements from one series of 194). Second setal row on vertex with 4 specimens that he thought were atypi- setae, inner 2 setae simple to denticulate, cally large. All of the newly collected outer 2 setae bifid (base ;0.5X length), colonies reported here have larger 0.08–0.11 mm long (Figs. 190, 193, workers that fall into the atypical ranges 194). Setae ventral to antenna level noted in parenthesis by Trager (1991). simple, 0.08–0.18 mm long (Figs. 190, Thus, this species is larger than first 193, 194). Clypeus with transverse row thought. In addition, some of the major of 4 setae, inner setae shorter than outer workers have their heads deeply emar- setae, 0.08–0.11 mm long. Labrum ginate posteriorly (Fig. 141), a distinc- small, short (breadth 2.4X length). La- tive feature that was not mentioned brum with 5 minute sensilla and 2 setae previously. on anterior surface of each half and Comments.—The gynes and workers ventral border with 4–6 sensilla on each of S. pusillignis superficially look like half. Each half of posterior surface of small S. macdonaghi. This species is labrum with 3–4 isolated and 2 contig- easily distinguished from S. macdonaghi uous sensilla. Straight medial portion of and others, however, by having yellow mandible with 2–5 teeth that decrease in workers with the posterodorsal and size dorsally (Fig. 192). Maxilla with posteroventral area of the propodeal apex conical, palpus peg-like with 5 spiracle granulate, and by having the sensilla, 1 bears spinule. Galea conical, heads of the largest workers deeply smaller than maxillary palpus, with 2 emarginate (Fig. 141). This species also apical sensilla, each bearing one spinule. has small gynes with small OOI mea- Labium with patch of spinules dorsal to surements and large OI measurements each palpus, spinules coarse and isolated and light-colored males with mesonotal or in short rows of 2–3. Labial palpus maculae. The gynes of S. pusillignis slightly elevated with 5 sensilla, each differ from S. electra in coloration of the bearing one spinule. gaster (S. pusillignis has a lighter gaster Body. Spiracles small, first spiracle and has a weakly developed T1 macu- larger than others. Body setae of 2 types. lation), and S. pusillignis has a less de- Simple setae (0.06–0.10 mm long) ar- veloped median clypeal tooth. ranged in transverse row of 4–5 on The males of S. pusillignis normally ventral surface of each thoracic somite have relatively large ocelli. This sug- and on each of 3 anterior abdominal gests that they may be nocturnally somites, some with short denticulate active. tips. Bifid setae (0.05–0.09 mm long) The larvae of this species are also occur elsewhere, base varying between distinct in having more setae on the head 0.2–0.5X length. capsule (10–12) than other species 356 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

(normally 8 or less). Also, some have absent, or more rarely poorly defined denticulate setae on the body, which (Fig. 32). Median clypeal tooth poorly differ from those found in some S. sae- developed, usually absent (Fig. 32). vissima by being denticulate only at the Approximately 0.50 of eye dorsal to mid- extreme apex. point of head (Fig. 32). Antenna usually 11-segmented, sometimes 10-segmented. Solenopsis pythia Santschi Mesosoma. Parapsidal lines present on posterior half of disk (Fig. 31). (Figs. 31, 32, 46, 51, 53) Mesonotum with distinct, median furrow Solenopsis pythia Santschi 1934: 30. on posterior 0.50 to 0.33 on disk. Pos- [Holotype gyne. ARGENTINA. Mis- terior margin of mesonotum angulate iones Province. Lorento. A. A. Oglobin. medially, bent anteriorly. Posterior mar- NHMB.] gin of scutellum sometimes angulate S. (Solenopsis) pythia Wilson 1952: 61. medially. Metasternum lacking median bidentate process. Wings not examined. Worker.—Head weakly ovate to sub- Metasoma. Lateral faces of post- quadrate. Head sculpture with small pilig- petiole strongly to slightly concave. erous foveolae, approximately 0.01 mm in Petiolar spiracle weakly tuberculate. diameter. Median frontal streak absent. Postpetiolar spiracle not tuberculate. Median ocellus absent in largest major Coloration, Sculpturing, and Pilosity. workers. Mandibular costulae present Piligerous foveolae large, conspicuous, throughout. Mesonotum with 20–25 se- width 0.010–0.020 mm in diameter tae. Promesonotal suture in largest major (Fig. 32), slightly larger on head than on workers gently curved medially. Meso- thorax and abdomen (Fig. 32). Dorsum notum weakly convex in lateral view. of mesosoma with distinctly piligerous Propodeum sculpture glabrous poster- foveolae (Fig. 51). Pubescence simple, oventral to spiracle. Postpetiole shape as golden and erect, of uniform length high as or higher than broad. Postpetiole (0.15–0.20 mm) (Fig. 53), longer and sculpture in posterior view with lower denser on head than elsewhere, longest 0.33–0.50 transversely rugose, upper on anterior edge of clypeus. Mandible surface glabrous and shiny. Color gener- with several coarse, distinct costulae ally orange brown, with frons, clypeus present throughout. Propodeum and and venter yellow brown. petiole postpetiole striato-rugulose Gyne.—Head. Slightly broader than throughout (Fig. 31). Postpetiole striato- long, quadrate, sides of head convex rugulose throughout, sometimes extreme from eyes to occipital angles, straight to dorsum glabrous (Fig. 46). In some ca- nearly straight ventral to eyes (Fig. 32). ses, sculpture of postpetiole tuberculate Eye normally with 2–4 several short se- and dorsum finely granulate. Inter- tae protruding from between ommatidia, foveolar spaces of head and pronotum setal length £3X width of ommatidium. finely striate; striae distinct to indis- Ocelli large, prominent (Fig. 32). Me- tinct (Fig. 32). Remaining interfoveolar dian ocellus circular, lateral ocelli spaces smooth and polished. Color yel- slightly ovate (Fig. 32). Clypeus pro- low orange with medial area of meso- jecting, carinal teeth stout and sharp, notum, parapsidal lines, lateral margins carinae weakly to moderately defined, of T1 and preapical transverse areas on less so dorsally, slightly divergent ven- gaster segments brown (Fig. 53). Internal trally (Fig. 32). Paracarinal teeth usually margins of ocelli sometimes brown. VOLUME 120, NUMBER 2 357

Morphometric Measurements. L ;5.3– unique that it is suspected to be a social 6.2, HW 1.3, VW 0.7–0.8, HL 1.0–1.1, parasite. Many of the gyne characters EL 0.4–0.5, OD 0.1–0.15, OOD 0.15– may actually be sympleisomorphic, as 0.25, LOW 0.08–0.12, MOW 0.10–0.12, they are shared with the gynes in the CD 0.14–0.16, MFC 0.15–0.18, EW S. molesta species-group. These charac- 0.35–0.40, SL 0.69–0.82, PDL 0.16– ters include a quadrate first flagellomere, 0.18, LF1 0.1, LF2 0.1, LF3 0.1, WF1 large and conspicuous piligerous foveo- 0.06–0.07, FL 0.91–1.02, FW 0.19–0.25, lae on the head and mesosoma, coarse MW 1.18–1.32, DLM 2.28–2.44, PRH costulae of the mandibles, thick and 0.90–1.03, PL 0.72–0.83, PND 0.61– coarsely sculptured petiolar node, short 0.73, PH 0.62–0.72, PPL 0.32–0.43, and subquadrate petiolar node, well de- DPW 0.49–0.84, PPW 0.48–0.61, PHB marcated posterior angles of propo- 0.58–0.71, N=7. deum, and absent bidentate process of Male.—Unknown. the metasternum. There are obvious Fourth instar worker larva.—Unknown. synapomorphic S. saevissima species- Material examined.—Specimens ex- group characters in S. pythia, however, amined were from Campo Grande, Mato such as the lack of a ventral petiolar Grosso do Sul, Brazil, Boctucatua, Sa˜o process in gynes and workers. Paulo State, Brazil (FSCA), and Posadas, Several dealated (wingless) gynes were Misiones Province, Argentina (JPPC, collected from a single nest, suggesting SDPC). that polygyny may occur in this species. Distribution.—Currently, this species is known from the material listed above Solenopsis quinquecuspis Forel and the type locality of Loreto, Misiones Province, Argentina (Fig. 202). (Figs. 33, 34, 43, 55, 66, 67, 81, 100, 101, Comments.—The major workers of 142, 143, 176, 178–181) S. pythia look like small workers of Solenopsis pylades var. quinquecuspis S. saevissima. The gynes, however, are Forel 1913: 224. [Syntype workers. easily recognized by having acute oc- ARGENTINA. Buenos Aires Province. cipital angles, large piligerous foveolae Bahia Blanca. 28-X-913 (=1913). of the head and mesosoma, coarse cos- Zelenko. NHMB.] tulae on the mandibles, a small OI, S. geminata saevissima var. quinque- a distinct median furrow on the posterior cuspis: Wheeler 1915: 397. 0.33 to 0.50 of the mesonotum, and a S. saevissima var.quinquecuspis:Santschi thick coarsely sculptured petiolar node. 1916: 381. Trager (1991) lists piligerous foveolae S. (Solenopsis) saevissima quinquecuspis: size as 0.01–0.15 mm: this must be Creighton 1930: 86. amisprintandshould read “0.010– S. blumi Buren 1972: 20. [NMNH.] 0.015 mm.” The petiolar node is shorter and subquadrate and the pos- Worker.—Head broad, cordate (Fig. terior angles of propodeum are more 143). Head sculpture with small pilig- defined than in S. saevissima.Thisis erous foveolae, approximately 0.01 mm the only species in the S. saevissima in diameter. Median frontal streak pres- species-group that lacks the bidentate ent, sometimes indistinct. Median ocel- metasternal process. lus in largest major workers present Solenopsis pythia has been suggested (absent in Fig. 143). Mandibular costulae by some (e.g., Trager 1991) to be so present throughout, sometimes obsolescent. 358 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Mesonotum with 20–25 setae. Prom- Coloration, Sculpturing, and Pilosity. esonotal suture in largest major workers Piligerous foveolae small, sparse, width angulate medially, sometimes projecting <0.01 mm in diameter, larger on head upward. Mesonotum in lateral view than on thorax and abdomen. Pubes- weakly convex (Fig. 142). Propodeum cence simple, pale brown to yellow and sculpture glabrous posteroventral to spi- erect, longer and denser on head than racle (Fig. 142). Propodeum in largest elsewhere, longest on anterior edge of major workers curves upward from met- clypeus. Mesosoma with longest pubes- anotal groove higher than flattened pos- cence (length >0.30 mm) 2X longer than terior portion, appearing as anterior raised shortest pubescence (Fig. 33). Mandible portion in lateral view. Postpetiole shape with 10–12 fine costulae. Propodeum much broader than high. Postpetiole in with fine striae throughout (Figs. 33, 55). posterior view with at least 0.75 trans- Posterior face of petiolar nodes with versely rugose to punctate-rugose, ru- 0.75 of lower surface finely striato- gosity sometimes extending to dorsum. granulate. Often, median striae of post- Color generally brown to dark brown on petiole obsolescent laterally; normally head, mesosoma, and median area of 11–13 striae present (Fig. 43). Dorsum petiole. Gaster dark brown. Frons, clyp- glabrous. Remaining integument smooth eus, and T1 maculation brown orange. and polished. Color generally red brown. Gyne.—Head. Slightly broader than Venter of head, frons and coxae orange long, quadrate, sides of head convex from yellow. Gaster dark brown, sometimes eyes to occipital angles, straight to nearly orange anteriorly. T1 and S1 orange on straight ventral to eyes (Fig. 34). Eye basal 0.50 of disk, blending to red brown sometimes with 3–12 setae protruding apically. Dark brown maculations pres- from between ommatidia, most setae £3X ent on mesonotum both anteromedially length of ommatidium, sometimes one or and on parapsidal lines (as in Fig. 52). two £4X length of ommatidium. Median Median longitudinal maculation some- ocellus moderate, circular (Fig. 34). Lat- times reaches scutellum. Internal mar- eral ocelli slightly ovate, small to moder- gins of ocelli not brown. Median frontal ate (Fig. 34). Clypeus projecting, carinal streak present (as in Fig. 50). teeth stout and sharp,carinaeindistinct Morphometric Measurements. L between scrobes, slightly divergent ven- ;7.1–7.7, HW 1.40–1.45, VW 0.81– trally (Fig. 34). Paracarinal teeth small, 0.95, HL 1.24–1.36, EL 0.40–0.44, OD usually well defined (Fig. 34). Median 0.13–0.16, OOD 0.15–0.20, LOW 0.11– clypeal tooth well developed (Fig. 34). 0.16, MOW 0.09–0.13, CD 0.17–0.20, Approximately 0.50 of eye dorsal to MFC 0.15–0.23, EW 0.30–0.34, SL midpoint of head (Fig. 34). 0.94–1.01, PDL 0.17–0.19, LF1 0.08– Mesosoma. Parapsidal lines present 0.11, LF2 0.07–0.10, LF3 0.06–0.09, on posterior 0.50 of disk (Fig. 33). WF1 0.06–0.07, FL 1.10–1.20, FW Mesonotum without posteromedian 0.26–0.31, MW 1.26–1.33, DLM 2.50– furrow. Bidentate medial process pres- 2.70, PRH 1.00–1.05, PL 0.65–0.72, ent on metasternum. Wing venation as PND 0.56–0.61, PH 0.66–0.75, PPL in Fig. 100. 0.25–0.34, DPW 0.50–0.71, PPW 0.60– Metasoma. Lateral faces of postpetiole 0.74, PHB 0.36–0.44, N=7. weakly concave to weakly convex. Petio- Male.—Head. Eye normally with 2–8 lar and postpetiolar spiracles slightly tu- setae protruding from between ommatidia, berculate in some cases. setae length £3X length of ommatidium. VOLUME 120, NUMBER 2 359

Ocelli large and prominent, elliptical Morphometric Measurements. L (Fig. 67). ;5.3–6.0, HW 1.02–1.10, VW 0.36– Mesosoma. Propodeum rounded, de- 0.41, HL 0.77–0.82, EL 0.46–0.50, OD clivous face perpendicular, flat except 0.09–0.12, OOD 0.14–0.23, LOW 0.10– with distinct to indistinct median longi- 0.14, MOW 0.11–0.14, CD 0.17–0.21, tudinal depression, basal face strongly MFC 0.10–0.15, EW 0.32–0.37, SL convex transversely and longitudinally. 0.15–0.23, SW 0.07–0.12, PDL 0.05– Metapleuron broad, ;0.66 as wide as 0.08, PEW 0.11–0.16, LF1 0.15–0.22, high (Fig. 66). Wing venation as in LF2 0.10–0.17, LF3 0.15–0.19, WF1 Fig. 101. 0.09–0.12, FL 1.05–1.22, FW 0.16–0.21, Metasoma. In cephalic view, dorsum MW 1.41–1.52, DLM 2.36–2.53, PRH of node with deep median impression, 0.90–0.96, PL 0.64–0.67, PND 0.54– bilobate, sometimes lobes curve poste- 0.60, PH 0.25–0.28, PPL 0.24–0.35, riorly. Petiolar spiracle distinctly tuber- DPW 0.50–0.62, PPW 0.61–0.70, PHB culate to not tuberculate. Postpetiolar 0.20–0.28, N=8. spiracle distinctly tuberculate. Genitalia Fourth instar worker larva.—Head. as in Fig. 81. Large, subpyriform in anterior view Coloration, Sculpturing, and Pilosity. (height 0.49 mm, width 0.55 mm) (Figs. Pubescence short, yellow, erect to sub- 176, 178). Cranium slightly broader than erect (0.25–0.30 mm in length) on mes- long (Figs. 176, 178). Antenna with 2 or onotum. Mesonotal pubescence dense 3 sensilla, each bearing spinule (Figs. (as in Fig. 73). Some shorter pubescence 176, 178). Occipital setal row with 6–8 (0.15 mm in length) also on mesonotum. simple setae, 0.09–0.13 mm long (Fig. Pubescence longest on gena and vertex. 181); rarely some specimens with 1–2 Propodeum with base striato-granulate, denticulate setae (Figs. 178, 180). First medially coarsely granulate (Fig. 66). setal row on vertex with 2 simple setae, Integument coarsely granulate on area 0.09–0.11 mm long (Figs. 176, 178). between eye and insertion of antenna, Second setal row on vertex with 4 simple area between ocelli, margins of meta- setae, 0.12–0.13 mm long (Figs. 176, pleuron, and base of petiolar node 178). Setae ventral to antenna level (Figs. 66, 67). Vertex and, sometimes, simple, 0.15–0.19 mm long (Figs. 176, gena striato-granulate. Head usually 178). Clypeus with transverse row of 4 glabrous and shiny anteroventral to lat- setae, inner setae shorter than outer se- eral ocelli. Head otherwise granulate. tae, 0.06–0.11 mm long (Figs. 176, 178). Pronotum granulate posteriorly. Meso- Labrum small, short (breadth 2X length), notum sometimes with coarsely granu- slightly narrowed medially (Figs. 176, late to striate margins. Posterior surface 178). Labrum with 4 sensilla and 2 setae of postpetiolar node coarsely granulate on anterior surface of each half. Ventral throughout, sometimes rugose. Lateral border with 4–6 sensilla on each half. faces of scutellum striate (Fig. 66). Re- Each half of posterior surface of labrum maining integument smooth and pol- with 2–3 isolated sensilla. Straight medial ished. Color generally dark brown to portion of mandible with 1–4 teeth that black, legs brown. Antennal scape, ped- decrease in size dorsally (Fig. 179). icel and first flagellum brown, distal Maxilla with apex conical, palpus peg-like portion of flagellum blending to yellow with 5 sensilla, each bearing one spinule. apically. Mandibles yellow brown to Galea conical with 2 apical sensilla, each brown. bearing one spinule. Labium with patch of 360 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON spinules dorsal to each palpus, in short rows other darker species. The pubescence is of 2–3. Labial palpus slightly elevated with longer and denser than in S. saevissima. 5sensilla,eachbearingonespinule. The S. quinquecuspis male normally is Body. Spiracles small, first spiracle more coarsely sculptured than S. mac- larger than others. Body setae of 2 types. donaghi. The gena is not granulate nor is Simple setae (0.04–0.10 mm long) ar- it as sculptured as in S. invicta. ranged in transverse row of 6–8 on The larvae of S. quinquecuspis are ventral surface of each thoracic somite distinct from the S. saevissima type by and on each of 3 anterior abdominal having simple setae on the head capsule. somites, some with short denticulate The larvae of S. quinquecuspis are sim- tips. Bifid setae (0.07–0.11 mm long) ilar to S. macdonaghi and S. megergates. occur elsewhere, base 0.5X length, Although the body of S. quinquecuspis is branches more or less perpendicular to larger and the setae on the body have base, tips recurved. Setae on thoracic a shorter base compared to S. macdon- dorsum with short base (<0.2X length). aghi, they are virtually indistinguish- Length. Approximately 3.8 mm. able. These larvae are much larger than Material examined.—Various speci- the larvae of S. richteri (as expected mens (FSCA). Also, see Appendix A. given adult worker size), and lack multi- Distribution.—The current range of branched setae and rugae on the head S. quinquecuspis extends south from Rio capsule. Grande do Sul, Brazil through Uruguay Studies of nuclear and mtDNA ge- and into Argentina (Fig. 202). In netic markers in S. quinquecuspis sug- Argentina, it occurs in Buenos Aires and gest that this species hybridizes with La Pampa Provinces and the eastern edges S. invicta and S. richteri in an area where of Santa Fe´ and Co´rdoba Provinces the ranges of all three species overlap, in (Fig. 202). the vicinity of Rosario, Santa Fe Province, Comments.—The gynes of S. quin- Argentina (Ross and Shoemaker 2005). In quecuspis are similar to the darker col- other areas of the range of S. quinque- ored gynes of S. invicta. However, the OI cuspis, there is no genetic evidence for of S. quinquecuspis is normally larger such hybridization (Ross and Trager than that of S. invicta. 1990). The gynes of the darker varieties of S. richteri could be confused for S. quinquecuspis. In this case, the mes- Solenopsis richteri Forel onotum of S. richteri is completely (Figs. 35, 36, 48, 68, 69, 82, 83, 102, 103, darkened and the mesonotal maculae are 144, 145, 185–189) indiscernible. Also for S. richteri, the maculation on the first segment of the Solenopsis pylades var. richteri Forel gaster covers the anterior 0.75 and it may 1909: 267. Syntype workers. [Syntype end abruptly posteriorly. For S. quin- workers, gynes, males. ARGENTINA. quecuspis the maculation fades out Buenos Aires. Richter. MHNG.] gradually posteriorly. For S. quinque- S. pylades var. tricuspis Forel 1912: 397. cuspis, this gaster maculation is only on Syntype workers. the anterior 0.50 or less and is never S. geminata saevissima var. richteri: distinctly margined posteriorly. Wheeler 1915: 397. The male of S. quinquecuspis is dark S. saevissima var. richteri: Santschi in coloration and is similar to most of the 1916: 281. VOLUME 120, NUMBER 2 361

S. saevissima var. tricuspis: Santschi developed (Fig. 36).Approximately 1916: 281. [NHMB?] 0.50 of eye dorsal to midpoint of head S. (Solenopsis) saevissima richteri: (Fig. 36). Creighton 1930: 87. Mesosoma. Parapsidal lines present S. saevissima var. oblongiceps Santschi on posterior 0.50 of disk (Fig. 35). 1936: 405. [NHMB] Mesonotum with indistinct, median fur- S. saevissima richteri: Wilson 1952: 66. row on posterior 0.25 or less. Bidentate S. richteri Buren 1972: 4. Worker, gyne, median process present on metasternum. male. Wing venation as in Fig. 102. Metasoma. Lateral faces of post- Worker.—Head ovate to weakly cor- petiole weakly to strongly concave. date (Fig. 145). Head sculpture with Petiolar and postpetiolar spiracles tu- small piligerous foveolae, <0.01 mm in berculate in some cases. diameter. Median frontal streak absent. Coloration, Sculpturing, and Pilosity. Median ocellus in largest major workers Piligerous foveolae small, sparse, width absent (Fig. 145). Mandibular costulae <0.01 mm in diameter, larger on head present, obsolescent medially. Humerus than on thorax and abdomen. Pubes- distinctly angulate, with distinct tu- cence simple, pale brown to yellow and berculate boss. Mesonotum with 20–26 erect, longer and denser on head than setae. Promesonotal suture curved medi- elsewhere, longest on anterior edge of ally, never projecting upward. Propodeum clypeus. Pubescence orange on T1 or- sculpture glabrous posteroventral to spi- ange integumental maculation. Meso- racle (Fig. 144). Postpetiole shape as high soma with longest pubescence (length as or higher than broad. Postpetiole with >0.30 mm) 2X longer than shortest lower 0.50 or less transversely rugose to pubescence (Fig. 35). Mandible with punctate-rugose, dorsum and face dorsal several coarse, distinct costulae, obso- to sculpture nitid, glabrous. Color gener- lescent medially. Propodeum with fine ally black with mandibles, lateral areas of striae posteriorly, anterior 0.25 polished clypeus, antennal fossae, mesosomal su- (Fig. 35). Posterior surface of petiolar tures, and T1 maculations dark brown to node with 0.75 of lower surface with fine yellow brown. striae, dorsum polished. Posterior sur- Gyne.—Head. Slightly broader than face of postpetiolar node with 0.75 of long, quadrate, sides of head convex lower surface finely striate, 12–14 striae from eyes to occipital angles, straight to present, median striae sometimes obso- nearly straight ventral to eyes (Fig. 36). lescent laterally (Fig. 48), dorsum is Eye sometimes with 3–4 setae pro- polished to slightly granulate. Remain- truding from between ommatidia, setal ing integument smooth and polished. length £3X width of ommatidium. Me- Two color forms exist. Dark form is dark dian ocellus large (Fig. 36). Lateral brown except antennal scape black, fla- ocelli small to moderate (Fig. 36). Me- gellum brown to orange, both T1 and S1 dian ocellus circular, lateral ocelli with medial orange maculation, other slightly ovate (Fig. 36). Clypeus pro- sternites brown with dark brown apices, jecting, carinal teeth stout and sharp, and petiole sometimes orange with dark carinae sometimes indistinct, less so dor- brown dorsum. Maculations on T1 and S1 sally, slightly divergent ventrally (Fig. 36). are well defined laterally and apically. Paracarinal teeth small, usually well de- Light form is orange except brown on fined (Fig. 36). Median clypeal tooth well vertex, around compound eyes, apically 362 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON on T1, and preapically on remaining tubercles higher than width of base. tergites. Both forms have dark brown Genitalia as in Figs. 82 and 83. maculations anteriorly on pronotum, Coloration, Sculpturing, and Pilosity. anteromedian area of mesonotum, area Pubescence short, yellow, erect to sub- around parapsidal lines, sometimes on erect and of uniform length over body median area of axillae, anteromedian and (0.15–0.20 mm), longest on gena and triangular posteromedian area of scutel- vertex. Mesonotal pubescence dense (as lum, medially on anepisternum, and me- in Fig. 73). Propodeum with base striato- dially and laterally on propodeum (as in granulate, medially glabrous (Fig. 68). Fig. 52). Both forms have dark brown Integument coarsely granulate in area finger-like projections of pigment from between eye and insertion of antenna, preapical tergal bands to apical setae. In- area between ocelli, pronotum, posterior ternal margins of ocelli dark brown. Me- portion of metapleuron, and base of peti- dian frontal streak usually absent, not olar node (Figs. 68, 69). Gena granulate, discernable from surrounding integument. sometimes weakly striato-granulate. Head Morphometric Measurements. L otherwise granulate. Posterior surface of ;7.5–8.5, HW 1.4–1.5, VW 1.0–1.2, HL postpetiolar node with lower 0.50 of sur- 1.2–1.3, EL 0.3–0.5, OD 0.1–0.2, OOD face striato-granulate, remainder polished. 0.15–0.20, LOW 0.08–0.10, MOW Metapleuron sometimes with striae both 0.10–0.15, CD 0.15–0.20, MFC 0.20– dorsally and ventrally. Lateral faces of 0.25, EW 0.30–0.40, SL 0.92–1.23, PDL scutellum striate (Fig. 68). Remaining in- 0.18–0.23, LF1 0.01–0.16, LF2 0.07– tegument smooth and polished. Color 0.1, LF3 0.08–0.11, WF1 0.07–0.10, FL generally red brown to black. Antennae 1.10–1.23, FW 0.21–0.32, MW 1.40– and legs yellow brown. Mandibles brown. 1.55, DLM 2.46–2.73, PRH 1.00–1.12, Morphometric Measurements. L PL 0.72–0.91, PND 0.51–0.60, PH 0.60– ;6.1–6.5, HW 1.0–1.1, VW 0.4–0.5, HL 0.72, PPL 0.39–0.53, DPW 0.59–0.69, 0.7–0.8, EL 0.4–0.5, OD 0.12–0.13, PPW 0.59–0.71, PHB 0.28–0.51, N=10. OOD 0.1–0.2, LOW 0.10–0.12, MOW Male.—Head. Eye normally with 2–4 0.10–0.15, CD 0.17–0.23, MFC 0.10– setae protruding from between ommatidia, 0.15, EW 0.3–0.40, SL 0.15–0.20, SW setal length £3X width of ommatidium. 0.1–0.12, PDL 0.08–0.10, PEW 0.10– Ocelli large and prominent, elliptical 0.14, LF1 0.15–0.25, LF2 0.12–0.15, (Fig. 69). LF3 0.14–0.16, WF1 0.07–0.11, FL 1.1– Mesosoma. Propodeum rounded, de- 1.2, FW 0.15–0.22, MW 1.39–1.52, clivous face perpendicular, flat except DLM 2.40–2.62, PRH 0.89–1.12, PL with distinct to indistinct median longi- 0.58–0.73, PND 0.51–0.60, PH 0.49– tudinal depression, basal face strongly 0.61, PPL 0.20–0.30, DPW 0.61–0.70, convex transversely and longitudinally. PPW 0.48–0.73, PHB 0.10–0.22, N=12. Metapleuron broad, ;0.66 as wide as high Fourth instar worker larva.—Head. (Fig. 68). Wing venation as in Fig. 103. Large, subpyriform in anterior view Metasoma. In cephalic view, dorsum (height 0.52 mm, width 0.55 mm) (Figs. of node transverse to having shallow 185, 189). Cranium slightly broader median impression and weakly bilobate, than long (Figs. 185, 189). Antenna with sometimes lobes curve posteriorly. Petio- 2or3sensilla,eachbearingspinule lar spiracles distinctly tuberculate to not (Figs. 185, 189). Integument of head tuberculate. Postpetiolar spiracle dis- with fine rugae. Occipital setal row with tinctly tuberculate to greatly tuberculate, 6–8 simple setae, 0.08–0.14 mm, rarely VOLUME 120, NUMBER 2 363 some specimens with single bifid to den- Argentina (Fig. 203). This species also ticulate seta, base ;0.8–0.95X total length has been introduced into North Amer- of seta (Fig. 185). First setal row on vertex ica, where it is currently confined to the with 2 simple setae, 0.09–0.11 mm long northwestern corner of Alabama, the (Figs. 185, 189). Second setal row on northeastern corner of Mississippi, and vertex with 4 simple setae, inner 2 setae south-central Tennessee. A broad S. richteri orientated farther from first setal row on x invicta hybrid zone exists south and east vertex, appear out of alignment with row, of the S. richteri range, including much 0.09–0.15 mm long (Figs. 185, 189). Se- of Mississippi, northern Alabama, and tae ventral to antenna level simple, 0.11– the northwestern corner of Georgia 0.18 mm long (Figs. 185, 189). Clypeus (Shoemaker et al. 1996, Gardner et al. with transverse row of 4 setae, inner setae 2008, Oliver et al. 2009). shorter than outer setae, 0.06–0.10 mm Comments.—The gynes of the lighter long (Figs. 185, 189). Labrum small, short varieties of S. richteri and S. interrupta (breadth 2.8X length), slightly narrowed are very similar in coloration due to the medially. Labrum with 4 minute sensilla first tergite of the gaster sometimes and 2 setae on dorsal surface of each half having an orange tergal maculation with and apex with 5–7 sensilla on each half. a distinct posterior margin. In many ca- Each half of epipharynx with 2–3 isolated ses, the gynes of these two species are sensilla. Straight medial portion of man- difficult to differentiate. However, they dible with 2–5 teeth that decrease in size differ in the sculpturing of the postpetiole. dorsally (Fig. 188). Maxilla with apex Also, S. richteri gynes are normally darker conical, palpus peg-like with 5 sensilla, in coloration and the OOI is much smaller each bearing one spinule. Galea conical than in S. interrupta.Theworkersof with 2 apical sensilla, each bearing one S. interrupta are larger than S. richteri and spinule. Labium with isolated patches of easily separated. Gynes of S. richteri in spinules dorsal to each palpus. Labial the United States are of the light form and palpus slightly elevated with 5 sensilla, are similar to those found in the northern each bearing one spinule. range of the species in southern Brazil. Body. Spiracles small, first spiracle This is probably the point of origin for the larger than others. Body setae of 3 types. United States population. Simple setae, slightly curved (0.08– The gynes of S. richteri from the 0.15 mm long), arranged in transverse row westernmost areas of the native range tend of 6–12 on ventral surface of each thoracic to be more darkly colored than the eastern somite and on each of 3 anterior abdom- representatives, resembling somewhat inal somites. Bifid setae (0.06–0.09 mm the darker S. invicta gynes. However, long) occur elsewhere, base ;0.5X length. S. richteri gynes are much darker in Multibranched setae occur rarely in the coloration and usually have a distinct area immediately posterior to head on tergal maculation on the gaster. Also, thoracic dorsum (Figs. 186, 187). the lateral margins of the postpetiole Length. 2.7–3.1 mm. are more concave than in S. invicta. Material examined.—Various speci- The gynes of S. richteri have weakly mens (FSCA). Also, see Appendix A. concave to straight lateral margins. Distribution.—In South America, the Males of S. richteri are similar in range of S. richteri extends from Parana´ coloration to many of the species within State, Brazil south and west from Mis- the species-group. However, the OOI iones Province to Mendoza Province in of S. richteri is much smaller than in 364 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

S. interrupta. Also, the males of S. richteri Solenopsis moelleri Forel 1904: 174. sometimes have a very distinct tuberculate [MHNG.] postpetiolar spiracle. Usually in pop- S. moelleri var. gracilior Forel 1904: ulations in the United States and in the 174. [MHNG?] southern part of the native range near S. geminata var. incrassata Forel 1908: Buenos Aires, the tuberculate postpetiolar 362. [MHNG?] spiracle is smaller and not as distinct. Males S. geminata pylades Forel 1909: 262. of S. richteri tend to have stronger sculp- S. saevissima var. morosa Santschi 1916: turing in the United States than they do in 380. [NHMB.] South America. S. geminata saevissima var. picea Wasmann The larval stage described by Wheeler 1918: 70. and Wheeler (1977) was collected in S. saevissima var. perfida Santschi 1923: Walker County, Alabama. At the time of 266. [NHMB.] collection, this area was likely part of the S. (Solenopsis) saevissima saevissima: S. richteri x invicta hybrid zone (Vander Creighton 1930: 80–83. Meer et al. 1985, Vander Meer and S. saevissima var. picea: Kistner 1982: Lofgren 1988). These specimens proba- 73–74. bly represent the larvae of S. richteri x invicta, rather than pure S. richteri. The Worker.—Head subquadrate to weakly description differs from that given above ovate (Fig. 147). Head sculpture with for S. richteri in several characters, the small piligerous foveolae, <0.01 mm in most conspicuous of which is the stated diameter. Median frontal streak absent. presence of bifid and denticulate setae on Median ocellus in largest major workers the head capsule. This is much more absent (Fig. 147). Mandibular costulae reminiscent of S. invicta. True S. richteri present throughout.Mesonotumwith larvae lack bifid setae on the head cap- 20–25 setae. Promesonotal suture in sule. The larvae differ from S. quinque- largest major workers gently curved cuspis by the presence of multi-branched medially, never projecting upward setae and fine rugae on the head capsule, (Fig. 146). Mesonotum weakly convex as well as being smaller in size. in lateral view (Fig. 146). Propodeum Genetic studies of S. richteri in its sculpture glabrous posteroventral to native range have revealed pronounced spiracle (Fig. 146). Postpetiole shape nuclear and mtDNA differentiation as high as or higher than broad. Post- between populations from southern petiole sculpture in posterior view with Brazil and central Argentina (Ross and lower 0.33–0.50 transversely rugose, Shoemaker 2005), consistent with upper surface glabrous and shiny. Color a long-term absence of gene flow be- generally red brown to dark brown. tween ants occupying these distant Gyne.—Head. Slightly broader than parts of its range. long, quadrate, sides of head convex from eyes to occipital angles, straight to Solenopsis saevissima (Smith) nearly straight ventral to eyes (Fig. 38). Eye sometimes with 3–4 setae pro- (Figs. 37, 38, 49, 70, 71, 73, 84, 85, 90, 91, truding from between ommatidia, setal 104, 105, 146, 147, 177, 182–184) length £3X width of ommatidium. Me- Myrmica saevissima F. Smith 1855: 166. dian ocellus large, circular (Fig. 38). [Syntype ? worker. BRAZIL. Para Lateral ocelli moderate to large, slightly State. Tapajo´s. Bates. BMNH.] ovate (Fig. 38). Clypeus projecting, VOLUME 120, NUMBER 2 365 carinal teeth stout and sharp, carinae and preapical transverse areas on well defined, less so dorsally, slightly metasomal segments. Internal margins divergent ventrally (Fig. 38). Paracarinal of ocelli dark brown. Median streak teeth small, sometimes poorly defined absent. (Fig. 38). Median clypeal tooth poorly Morphometric Measurements. L developed, usually absent (Fig. 38). ;7.1–8.0, HW 1.3–1.8, VW 0.5–0.9, HL Approximately 0.50 of eye dorsal to 1.2–1.3, EL 0.4–0.6, OD 0.1–0.2, OOD midpoint of head (Fig. 38). 0.15–0.25, LOW 0.08–0.15, MOW 0.13– Mesosoma. Parapsidal lines present 0.16, CD 0.15–0.22, MFC 0.20–0.25, EW on posterior 0.50 of disk (Fig. 37). Mes- 0.25–0.40, SL 0.89–1.12, PDL 0.18–0.25, onotum with indistinct, median furrow on LF1 0.1–0.14, LF2 0.07–0.1, LF3 0.07– posterior one-sixth or less. Median bi- 0.12, WF1 0.09–0.12, FL 1.00–1.2, FW dentate process present on metasternum. 0.19–0.31, MW 1.32–1.43, DLM 2.53– Wing venation as in Figs. 90, 104. 2.81, PRH 0.98–1.10, PL 0.58–0.82, PND Metasoma. Lateral faces of post- 0.51–0.61, PH 0.52–0.83, PPL 0.28–0.43, petiole weakly to strongly concave. DPW 0.48–0.83, PPW 0.60–0.91, PHB Petiolar and postpetiolar spiracles tu- 0.27–0.51, N=13. berculate in some cases. Male.—Head. Eye normally without Coloration, Sculpturing, and Pilosity. setae protruding from between omma- Piligerous foveolae small, sparse, width tidia. Ocelli large and prominent, elliptical <0.01 mm in diameter, larger on head (Fig. 71). than on thorax and abdomen. Pubes- Mesosoma. Propodeum rounded, de- cence simple, golden and erect, longer clivous face perpendicular, flat except and denser on head than elsewhere, with distinct to indistinct median longi- longest on anterior edge of clypeus. tudinal depression, basal face strongly Mesosoma with longest pubescence convex transversely and longitudinally. (length >0.30 mm) 2X longer than Metapleuron sometimes not broad, ;0.33 shortest pubescence (Fig. 37). Mandible as wide as high, but usually broader with 9–11 fine, distinct costulae present (Fig. 70), sometimes with transverse throughout. Propodeum with fine striae posterior carina. Wing venation as in posteriorly, anterior 0.25 polished (Fig. 37). Figs. 91 and 105. Posterior surface of petiolar node with Metasoma. In cephalic view, dorsum lower 0.75 of surface with fine striae, of node varies from transverse to bilo- dorsum polished. Posterior surface of bate with deep median impression. Pet- postpetiolar node with lower 0.75 of iolar and postpetiolar spiracles distinctly surface with coarse striae, 4–7 striae tuberculate to not tuberculate. Genitalia present, median striae weak to obsoles- as in Figs. 84 and 85. cent laterally, dorsum polished (Fig. 49). Coloration, Sculpturing, and Pilosity. Remaining integument smooth and pol- Pubescence short, thin, yellow, erect to ished. Color varies from dark brown to suberect and of uniform length over pale yellow on front of head, lateral body (0.15–0.20 mm), longest on gena portions of mesonotum, mandibles, and vertex. Mesonotal pubescence mesosternum, appendages and apical sparse (Fig. 72). Propodeum with base portions of gaster segments. Color striato-granulate, medially finely granu- brown on vertex, interior margins of late (Fig. 70). Area between eye and ocelli, medial area of mesonotum, insertion of antenna, area between ocelli, parapsidal lines, lateral margins of T1 posterior portion of metapleuron, and 366 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON base of petiolar nodes granulate to setae, inner setae shorter than outer se- weakly granulate (Figs. 70, 71). Vertex tae, 0.03–0.09 mm long (Figs. 177, 182). posterior to ocellar triangle glabrous Labrum small, short (breadth 2.3X (Fig. 71). Gena weakly striate. Posterior length) (Figs. 177, 182). Labrum with surface of petiolar node with lower 0.25 4–6 sensilla on dorsal surface of each of surface with fine striae, lower 0.50 of half and apex with coarse isolated spi- surface granulate, sometimes granula- nules. Each half of epipharynx with 2–3 tions obsolescent medially, dorsum pol- isolated and 2 contiguous sensilla. ished. Lateral faces of the scutellum Straight medial portion of mandible striate. Remaining integument smooth with 2–5 teeth that decrease in size and polished. Color generally red yellow dorsally. Maxilla with apex conical, to yellow brown. Antennae and legs pale palpus peg-like with 5 sensilla, 2 with yellow. Mandibles yellow. spinules. Galea conical with 2 apical Morphometric Measurements. L sensilla, each bearing one spinule. ;6.0–7.5, HW 0.89–1.10, VW 0.28– Labium with patch of spinules dorsal to 0.51, HL 0.70–0.81, EL 0.40–0.62, OD each palpus, spinules coarse and iso- 0.05–0.11, OOD 0.18–0.32, LOW 0.10– lated or in short rows of 2–3. Labial 0.22, MOW 0.15–0.25, CD 0.15–0.25, palpus slightly elevated with 4–5 sen- MFC 0.15–0.21, EW 0.30–0.40, SL silla, each bearing one spinule. 0.15–0.20, SW 0.09–0.15, PDL 0.05– Body.Spiraclessmall,firstspiracle 0.12, PEW 0.09–0.15, LF1 0.10–0.21, slightly larger than others. Body setae LF2 0.10–0.15, LF3 0.15–0.20, WF1 of 2 types. Simple to denticulate setae 0.09–0.10, FL 1.00–1.12, FW 0.15–0.21, (0.05–0.13 mm long) arranged in MW 1.18–1.64, DLM 2.10–2.82, PRH transverse row of 6–8 on ventral sur- 0.77–1.12, PL 0.50–0.61, PND 0.38– face of each thoracic somite and on 0.60, PH 0.30–0.61, PPL 0.18–0.44, each of 3 anterior abdominal somites. DPW 0.40–1.03, PPW 0.43–0.94, PHB Bifid setae (0.05–0.08 mm long) occur 0.30–0.40, N=12. elsewhere, base ;0.5X length (Figs. Fourth instar worker larva.—Head. 183, 184). Large, subpyriform in anterior view Length. Approximately 2.3 mm. (height 0.40 mm, width 0.43 mm) (Figs. Material examined.—Various speci- 177, 182). Cranium slightly broader than mens (FSCA). Also, see Appendices A long (Figs. 177, 182). Antenna with 3 and B. sensilla, bearing spinule (Figs. 177, Distribution.—A light color variant 182). Occipital setal row with 4–8 bifid of S. saevissima occurs throughout the setae, base 0.5–0.66X total length of Amazon basin (Fig. 201). The dark color seta, 0.03–0.07 mm long (Figs. 177, 182, variant occurs south from Goais and 183). First setal row on vertex with 2 Bahia to Sa˜o Palo State in Brazil (Fig. bifid setae, base ;0.66X total length of 201). The dark color variant occurs seta, setae 0.03–0.07 mm long (Figs. sporadically throughout the Amazon 177, 182, 183). Second setal row on basin. vertex with 4 setae, inner 2 setae simple, Comments.—This species is highly outer 2 setae with denticulate to bifid variable in both coloration and size of apices, 0.09–0.10 mm long (Figs. 177, the workers and gynes. They range from 182, 183). Setae ventral to antenna level the small dark forms in southern Brazil simple, 0.12–0.14 mm long (Figs. 177, to the large orange brown forms in 182). Clypeus with transverse row of 4 northern Brazil. These color forms are VOLUME 120, NUMBER 2 367 not morphologically distinct, however, et al. 2010). In particular, specimens from as there is an almost continuous cline in Amazonian, southeastern Atlantic, and size and coloration. Recently, Ross et al. south-central Atlantic portions of the (2010) were able to distinguish five Brazilian range are highly divergent evolutionary independent lineages in from specimens collected in central nominal S. saevissima using genetic Brazil. The various color forms in this data (see Fig. 201). Discovery of differ- species are not concordant with the entiating characters and formal descrip- major genetic lineages. tion of these putative species is still outstanding. Solenopsis weyrauchi Trager The gynes of S. saevissima lack meso- notal maculae like S. electra, S. pusillignis, Solenopsis weyrauchi Trager 1991: 190. and S. macdonaghi.Contrarytothis,some [Holotype worker. “Abra Gavila´nb. callow gynes have integumental macula- Caramarca, 2, 800 m. PERU. #709. tions on the mesonotum. These macula- ex. col. Weyrauch. LACM.] tions are not distinctly margined and must fade as the gyne matures. Worker.—Head ovate to subrectangular. There is a large size variation of the Head sculpture with small piligerous males as well. However, the distribution foveolae, ;0.01 mm in diameter. Me- is opposite to that of the workers and dian frontal streak present, sometimes gynes. The larger males are normally consisting of 2 elongate darkened found within colonies of the smaller, spots. Median ocellus in largest major dark-form workers. workers absent. Mandibular costulae Males of S. saevissima are most sim- usually well developed throughout ilar to S. pusillignis due to their lighter entire length, sometimes obsolescent coloration and to the region of the head near base. Mesonotum with 30 or more posterior to the ocellar triangle being setae. Promesonotal suture in largest glabrous. The males of S. saevissima major workers gently curved medially, lack the large ocelli and mesonotal never projecting upward. Mesonotum maculations possessed by males of weakly convex in lateral view. Propo- S. pusillignis.MalesofS. saevissima deum sculpture glabrous posteroventral tend to have the OOI (2.50–3.50) larger to spiracle. Postpetiole shape as high than any other species (<2.70). as or higher than broad. Postpetiole The larvae of S. saevissima are similar sculpture in posterior view with lower to S. invicta.AlthoughS. saevissima lar- 0.50–0.75 transversely rugose, upper vae normally have a smaller head capsule surface shiny with some piligerous than S. invicta, the setal characters are foveolae present. Color of head, mes- similar between the two species. Some onotum and T1 maculation red yellow. larval specimens of S. saevissima have Remainder of gaster black brown. Pro- denticulate setae present on the body, podeum and dorsum of petiolar nodes which differs from S. invicta. yellow brown. Sometimes rear portion As is the case with S. invicta and of head, frons around median streak, S. richteri,extremegeneticdifferentiation and pronotum yellow brown. T1 of geographic populations of S. sae- maculations with 2 small anterolateral vissima has been detected using mtDNA spots. sequence data as well as nuclear micro- Gyne.—Unavailable for study. satellite data (Shoemaker et al. 2006, Ross Male.—Unknown. 368 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Fourth instar worker larva.— This species-group is presumably closely Unknown. related to the S. nigella species-group Material examined.—Three speci- sensu Moreno-Gonzalez (2001), which is mens from Bolivia, 6 km northeast of equivalent to Euopthalma of Creighton Potosı´, 19° 32’ S, 65° 43’ W, 3900 m, 25. minus S. globularia. XII.1993, P.S. Ward (UCDC). These Solenopsis tridens and S. substituta specimens were identified by J. C. are placed in the S. tridens species- Trager. group, which is defined by mono- Distribution.—Solenopsis weyrauchi morphic workers with a long scape, long was previously known only from several first flagellomere (at least 1.5X longer widely spaced locations at high eleva- than broad), propodeal carinae, and an tions in the Peruvian Andes. The holotype elongate petiolar peduncle. This species- (unavailable for study) is from Cajamarca, group is equivalent to the S. tridens Peru (Fig. 201). As the new locality data complex of Trager. suggest and as Trager (1991) predicted, The S. geminata species-group in- the range of S. weyrauchi likely extends cludes S. geminata, S. xyloni, S. am- throughout the Andes, at least from Peru blychila, S. aurea, S. gayi, and S. bruesi. to Bolivia, but perhaps as far northward as This species-group is defined by strongly Columbia and southward as Argentina polymorphic workers with a short and Chile. scape, long first flagellomere (at least 1.5X longer than broad), reduced or

DISCUSSION absent median clypeal tooth, and aventralpetiolarprocess.Thisspecies- Delineation of Species Groups within group is equivalent to the S. geminata Solenopsis complex of Trager. No apomorphies Trager (1991) placed the worker-poly- are apparent for the species-group, and morphic fire ants along with three mono- it may be defined entirely by symple- morphic Solenopsis species (S. substituta, siomorphies. S. tridens, and S. virulens)intheS. gem- Finally, the S. saevissima species-group inata species-group, although he admitted includes S. metallica n. sp., S. daguerrei, the inclusion of S. virulens was some- S. electra, S. hostilis, S. interrupta, S. in- what arbitrary. Trager referred to smaller victa, S. macdonaghi, S. megergates, groupings within the S. geminata species- S. pusillignis, S. pythia, S. quinquecuspis, group as species complexes, and sub- S. richteri, S. saevissima, and S. weyr- sets of complexes as subcomplexes. auchi. This group is defined by strongly The S. geminata species-group is informal polymorphic workers with a long scape, and its monophyly has yet to be demon- long first flagellomere (at least 1.5X lon- strated. This situation, coupled with the ger than broad), strongly developed me- unwieldy terminology of complexes and dian clypeal tooth, weak sculpturing, and subcomplexes, has led us to propose a new a small or absent ventral petiolar process. classification of fire ants (Table 4). This species-group is equivalent to the Solenopsis virulens is placed in the S. saevissima complex of Trager. S. virulens species-group, which is de- There is some molecular support for fined by the following: workers mono- the monophyly of these groups (Krieger morphic, eye small with 20–60 facets, and Ross 2005, Shoemaker et al. 2006), first flagellomere as broad as or broader although taxon sampling is incomplete than long, and postpetiole not dilated. and branch support is often weak. As VOLUME 120, NUMBER 2 369 such, the proposed species complexes the likelihood that related species would should be viewed as preliminary until become similar in this structure through the evolutionary relationships of the fire parallelism is low (Mayr 1969). Thus, ants have been robustly estimated using genitalic characters are potentially useful diverse charcter sets. for distinguishing even closely related species. This is not the case for Sol- Morphology of Sexuals enopsis. Although there are slight differ- Creighton (1930, 1950) stated that ences between the S. fugax species-group both males and gynes of Solenopsis ap- and several of the other fire ant species- pear to offer better characters for specific groups, this study found that the male determinations than do the workers. genitalia of the species within the Because individuals of the sexual caste S. saevissima species-group were rela- tend to be larger than the worker caste tively homogeneous and uninformative and have a less generalized and reduced (Figs. 74–86). After study of the genitalia anatomy, they could provide characters, of many Solenopsis exemplars, we also such as those from male genitalia and conclude that characters used by Baroni- wing venation, that are not obtainable Urbani (1968) to raise Diplorhoptrum to from workers and are useful for identi- the generic level are not found in all of fication purposes (Creighton 1930, 1950). the species he placed in this taxon. This study found that the amount of in- Furthermore, Diplorhoptrum species traspecific variation occurring in the adult such as S. tennesseensis and S. abdita males and gynes was equivalent to that have genitalia more closely resembling of workers, making the taxonomic in- those of the fire ants than those of the formation gained from these castes no European Diplorhoptrum species, S. fugax. better than that obtained from workers. This information provides additional Furthermore, the morphometric mea- support for the synonymy of Diplorhop- surements and indices (Tables 5, 6) of trum with Solenopsis,asproposedby the adult males and gynes alone are Bolton (1987). inadequate for determining species. Given a choice, workers still offer the Wing Venation most reliable and numerous characters, Although wing venation in Solenopsis and these characters alone usually are may provide valuable data for inferring sufficient for making accurate species the higher-level phylogeny of the tribe identifications. Even though the mor- Solenopsidini in the future, as proposed by phology and morphometrics of sexuals Brown and Nutting (1950), it appears to be are of limited use alone, they greatly too conservative within the S. saevissima improve the accuracy of identifications species-group to be phylogenetically of fire ants when used in concert with informative (Pitts et al. 2005). More- data for the workers. over, wing venation tends to be too Male Genitalia similar across species and too variable For many Hymenoptera, the male within species (Figs. 87–108) to pro- genitalia are of great diagnostic utility. vide diagnostic information. Sexual selection is hypothesized to often Although some slight differences ex- drive the rapid divergence of the mor- ist, the wing venation of the S. saevissima phology of male genitalia once specia- species-group is remarkably similar to that tion occurs (Eberhard 1985). Also, because of other groups, such as the S. geminata the male genitalia are structurally complex, species-group (Figs. 109-114, 116), the 370 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

S. tridens species-group (Figs. 115, lack of the m-cu cross vein for S. met- 117, 118), the S. globularia species- allica was observed in all four forewings group (Fig. 123), and some members of of the two gynes from different nests the S. molesta species-group (Figs. 124– examined. All specimens of S. daguerrei 125). Furthermore, distantly related spe- had reduced wing venation, albeit to cies such as S. nigella gensterblumi, S. nr. various degrees. nigella, and an unidentified Solenopsis Other observed morphological ab- species are similar in their venation as normalities are noted here. A single gyne well (Figs. 119–122). Some species in of S. megergates had two median ocelli the S. molesta species-group have di- and had coarse striations throughout the agnostic wing venation, such as the re- ocellar triangle (Fig. 54). These com- duction of the r-rs cross vein (Fig. 129), plete striations were seen only in this but others do not (Figs. 127–129). In single atypical specimen. One gyne of general, wing venation provides few S. quinquecuspis had four propodeal taxonomically informative characters spiracles (Fig. 55). These two speci- for the genus. mens did not otherwise differ from the Intraspecific variation and individual typical gynes of their species. Lastly, aberrations in wing venation were com- two gynandromorphs of S. quinque- monly observed, including: 1) swelling cuspis were discovered, as will be in the Rs+M vein in the radial cell of discussed elsewhere. a S. pusillignis gyne (Fig. 87) and S. richteri gyne (Fig. 102); 2) coarseness of the Rs Larval Morphology vein and the veins delineating the radial Wheeler and Wheeler (1976, 1986, cell in individuals of several species 1991) found that larval morphology (Figs. 89, 93, 95); 3) swellings on the Cu could be used to differentiate ant genera vein of a S. macdonaghi male (Fig. 97); and provided a generic key using larval 4) swellings on the Rs+M vein in the characters. In some cases, higher level median cell of a S. megergates gyne taxonomy of Formicidae has been re- (Fig. 98). These abnormalities are found defined using larval morphology (Wheeler in other species-groups and are probably and Wheeler 1970). Many species-level characteristic of the genus Solenopsis as larval descriptions have been published a whole (Figs. 109, 119, 122, 125) (see for Formicidae, but in only three cases has also Ross and Robertson 1990). In some larval morphology been used for phylo- cases, certain veins are misplaced so that genetic purposes (Wheeler and Wheeler the venation looks unique (Fig. 109), but 1970, Schultz and Meier 1995, Pitts et al. usually the other wing on the same in- 2005). dividual is normal. Such asymmetry has The larval stages of ten species within been documented for Oxyepoecus, a close the Solenopsis saevissima species-group relative of Solenopsis (Kempf 1974). This are described in this study, eight for the variation exists as well for both spectral first time. The morphology of these and nebulous veins. species is very similar, yet some var- The lack of the m-cu cross vein for the iation occurs. Wheeler and Wheeler gynes of S. metallica (Fig. 89) and the (1977) reported that S. invicta differed reduction of wing venation in S. da- from S. richteri x invicta (described as guerrei (Figs. 106, 108) are constant for S. richteri) in the number of setae on the all specimens seen and are considered dorsal side of the labrum and the number characters rather than abnormalities. The of sensilla on the ventral margin of the VOLUME 120, NUMBER 2 371 labrum. The present survey of many de Investigacio´nenInteraccionesBio- specimens and species revealed that lo´gicas, Universidad Nacional de Quilmes, minute features such as these are quite Buenos Aires, Argentina), J. Heraty (De- variable within species and thus are not partment of Entomology, University of very useful in species determinations. California at Riverside), C. Kugler (Bi- Mandibular dentition is of limited use ology Department, Radford University, due to varying degrees of wear resulting Virginia), T. R. Schultz (NMNH), R. R. from feeding. Solenopsis saevissima Snelling (LACM), J. C. Trager (Shaw Ar- species-group larvae are of little sys- boretum of Missouri Botanical Gardens, tematic significance because most larval Missouri), D. B. Wahl (AEIC), and features are broadly overlapping and J. Wheeler for providing information continuous among species. However, and advice for this project. We are two general groups of species can be grateful for J. Wiley’s effort in providing defined on the basis of larval characters. access to the large alcohol collection of One group includes those species with Solenopsis from the FSCA. We are bifid setae dorsal to the antennal margin thankful for the assistance provided by (S. metallica,n.sp.,S. interrupta, S. invicta, M. A. Farmer and J. A. Shields of the S. pusillignis, S. saevissima), a condition Center of Ultrastructural Studies, Uni- termed the S. saevissima type. The other versity of Georgia for SEM support. The group contains those species with setae following institutions provided support to dorsal to the antennal margin that are usu- JPP for this study: the Canadian National ally simple or dentate (S. macdonaghi, Collection for a CanaColl grant for S. megergates, S. quinquecuspis,and travel to Ottawa, Canada in 1999, and S. richteri), a condition termed the S. me- the American Museum of Natural gergates type. This latter type appears History for a Theodore Roosevelt on the basis of the inferred species Memorial Fund grant for travel to the phylogeny to be the apomorphic con- Southwestern Research Station, Por- dition in the species-group (Pitts et al. tal, Arizona during 2000. We thank 2005). W. Sherbrooke for his hospitality and help during JPP’s stay at the South- western Research Station, M. C. ACKNOWLEDGMENTS Mescher for important logistic support We thank T. L. Pitts-Singer (USDA- in South America, and T. L. Pitts- ARS Bee Biology and Systematics Singer for collecting assistance while Laboratory, Logan, Utah), S. D. Porter at the SWRS. JPP is also grateful for (USDA-ARS), and Colin Brammer the financial support provided by the (Department of Biology, Utah State University of Georgia, Department of University, Logan) for critically review- Entomology. GPC is grateful for the ing drafts of this paper; S. Cover (MCZ), financial support provided by the C. Flechtmann (ICIB), L. E. Gilbert Smithsonian Institution Peter Buck (Department of Zoology, University of Fellowship. This research was funded Texas, Austin), J. T. Huber (CNCI), I. by United States Department of Agri- Lo¨bl (MHNG), S. D. Porter (USDA- culture grant 99–35302–8629 provided ARS), L.A. Stange (FSCA), L. Calca- to KGR, JVM, and D. D. Shoemaker and terra (USDA-ARS), and P. S. Ward National Science Foundation grant (UCDC) for loans of specimens; J. M. DEB-1354479 to KGR and D. D. Carpenter (AMNH), P. Folgarait (Unidad Shoemaker. 372 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

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Figs. 1‒5. 1, Head of Solenopsis gyne, dorsal view. 2, Mesosoma of Solenopsis gyne, dorsal view. 3, Mesosoma of Solenopsis worker, lateral view. 4, Head of Solenopsis gyne, lateral view. 5, Mesosoma of Solenopsis gyne, lateral view. (anepisternum (an), axillae (ax), compound eyes (ce),ocelli(oc),clypealteeth(cc), katepisternum (k), median tooth (mct), mesonotum (mes), metanotum (met), metapleural spiracle (mts), meta- pleuron (mtp), mesopleuron (msp), parapsidal lines (pl), propodeum (ppm), postpetiole (ppt), pronotum (prn), petiole (pt), and scutellum (sct)). 378 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 6‒7. 6, Head of Solenopsis gyne with measurements noted, dorsal view. 7, Mesosoma of Solenopsis worker, lateral view. VOLUME 120, NUMBER 2 379

Figs. 8‒10. 8, Petiole of Solenopsis gyne with measurements noted, lateral view. 9, Head and mesosoma of Solenopsis male, lateral view. 10, Head of Solenopsis male, dorsal view. (anepisternum (an), axillae (ax), compound eyes (ce), katepisternum (k), mesonotum (mes), metanotum (met), meso- pleuron (msp), metapleuron (mt), ocelli (oc), parapsidal lines (pl), propodeum (ppm), postpetiole (ppt), pronotum (prn), petiole (pt), and scutellum (sct)). 380 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 11‒15. 11, Forewing of Solenopsis gyne showing wing venation. 12, Larval head capsule of typical Solenopsis. 13, Solenopsis larval head capsule, occipital setal row darkened. 14, Solenopsis larval head capsule, first setal row on vertex darkened. 15, Solenopsis larval head capsule, second setal row on vertex darkened. VOLUME 120, NUMBER 2 381

Figs. 16‒22. 16, Head of major worker of Solenopsis metallica sp. nov., dorsal view, scale = 0.22 mm. 17, Head of minor worker of S. metallica sp. nov., dorsal view, scale = 0.22 mm. 18, Mesosoma of major worker of S. metallica sp. nov., lateral view, scale = 0.22 mm (pms = promesonotal suture). 19, Postpetiole of major worker of S. metallica sp. nov., rear view, scale = 0.22 mm. 20, Head of gyne of S. metallica sp. nov., dorsal view, scale = 0.22 mm. 21, Mesosoma of gyne of S. interrupta, lateral view. 22, Head of gyne of S. interrupta,dorsalview. 382 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 23‒28. Solenopsis gynes. 23, Mesosoma, S. invicta,lateral.24,Head,S. invicta,dorsal. 25, Mesosoma, S. macdonaghi, latera. 26, Head, S. macdonaghi, dorsal. 27, Mesosoma, S. megergates, lateral. 28, Head, S. megergates, dorsal. VOLUME 120, NUMBER 2 383

Figs. 29‒34. Solenopsis gynes. 29, Mesosoma, S. pusillignis, lateral. 30, Head, S. pusillignis, dorsal. 31, Mesosoma, S. pythia,lateral.32,Head,S. pythia,dorsal.33,MesosomaS. quinquecuspis,lateral. 34, Head, S. quinquecuspis,dorsal. 384 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 35‒40. Solenopsis gynes. 35, Mesosoma, S. richteri,lateral.36,Head,S. richteri,dorsal. 37, Mesosoma, S. saevissima, lateral. 38, Head, S. saevissima, dorsal. 39, Mesosoma, S. electra, lateral. 40, Head, S. electra, dorsal. VOLUME 120, NUMBER 2 385

Figs. 41‒52. Postpetiole of Solenopsis gynes, posterior view. 41, S. macdonaghi.42,S. invicta. 43, S. quinquecuspis.44,S. metallica sp. nov. 45, S. pusillignis.46,S. pythia.47,S. interrupta.48,S. richteri. 49, S. saevissima. Solenopsis gynes. 50, Head of Solenopsis sp. with median frontal steak (fs), dorsal view. 51, Mesosoma of S. pythia showing large foveolae, dorsal view. 52, Mesosoma of Solenopsis sp. showing maculae, dorsal view. 386 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 53‒57. Solenopsis spp. gynes, mesonoma, and head. 53, S. pythia, lateral view. 54, Ocellar triangle of Solenopsis quinquecuspis gyne with two median ocelli, dorsal view. 55, Propodeum of S. quinquecuspis gyne with four propodeal spiracles, lateral view. 56, Mesosoma of male of S. interrupta, lateral view. 57, Head of male of S. interrupta, dorsal view. VOLUME 120, NUMBER 2 387

Figs. 58‒63. Solenopsis males. 58, Mesosoma of S. invicta, lateral view. 59, Head of S. invicta, dorsal view. 60, Mesosoma of S. macdonaghi, lateral view. 61, Head of S. macdonaghi, dorsal view. 62, Mesosoma of S. megergates, lateral view. 63, Head of S. megergates, dorsal view. 388 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 64‒69. Solenopsis males. 64, Mesosoma of S. pusillignis, lateral view. 65, Head of S. pu- sillignis, dorsal view. 66, Mesosoma of S. quinquecuspis, lateral view. 67, Head of S. quinquecuspis, dorsal view. 68, Mesosoma of S. richteri, lateral view. 69, Head of S. richteri, dorsal view. VOLUME 120, NUMBER 2 389

Figs. 70‒74. Solenopsis males. 70, Mesosoma of S. saevissima, lateral view. 71, Head of S. sae- vissima, dorsal view. 72, Mesosomal dorsum of S. saevissima, dark form, lateral view. 73, Mesosomal dorsum of S. interrupta, dark form, lateral view. 74, Genitalia of S. interrupta, aedeagus, upper, scale = 62 mm (dorsal apodeme (ap)); volsella, lower, scale = 25 mm (cuspis (cus) and digitus (dig)). 390 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 75‒78. Genitalia of male. 75, Solenopsis invicta. 76, S. macdonaghi. 77, S. macdonaghi. 78, S. megergates, aedeagus; upper, scale = 62 mm, volsella; lower, scale = 25 mm. VOLUME 120, NUMBER 2 391

Figs. 79‒82. Genitalia of male. 79, Solenopsis megergates. 80, S. pusillignis. 81, S. quinquecuspis. 82, S. richteri; aedeagus, upper, scale = 62 mm; volsella, lower, scale = 25 mm. 392 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 83‒86. 83, Genitalia of male: Solenopsis richteri. 84, S. saevissima. 85, S. saevissima. 86, S. daguerrei; aedeagus, upper, scale = 62 mm; volsella, lower, scale = 25 mm. VOLUME 120, NUMBER 2 393

Figs. 87‒91. Solenopsis wings. 87, Forewing of S. pusillignis gyne. 88, Forewing of S. pusillignis male. 89, S. metallica sp. nov. gyne. 90, S. saevissima gyne, light form. 91, S. saevissima male, light form; scale = 350 mm. 394 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 92‒97. Solenopsis wings. 92, S. interrupta gyne. 93, Forewing of S. interrupta male. 94, Forewing of S. invicta gyne. 95, Forewing of S. invicta male. 96, Forewing of S. macdonaghi gyne. 97, Forewing of S. macdonaghi male, scale = 350 mm. VOLUME 120, NUMBER 2 395

Figs. 98‒105. Solenopsis wings. 98, S. megergates gyne. 99, S. megergates male. 100, Forewing of S. quinquecuspis gyne. 101, S. quinquecuspis male. 102, Forewing of S. richteri gyne. 103, Forewing of S. richteri male. 104, S. saevissima gyne. 105, Forewing of S. saevissima male, scale = 350 mm. 396 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 106‒112. Solenopsis wings. 106, S. daguerrei gyne. 107, S. electra gyne. 108, S. daguerrei male. 109, S. geminata gyne. 110, Forewing of S. geminata male. 111, Forewing of S. xyloni gyne. 112, Forewing of S. xyloni male, scale = 350 mm. VOLUME 120, NUMBER 2 397

Figs. 113‒119. Solenopsis wings. 113, S. amblychila gyne. 114, Forewing of S. amblychila male. 115, S. tridens gyne. 116, S. aurea gyne. 117, S. substituta gyne. 118, S. amblychila male. 119, Forewing of S. nr. nigella gyne, scale = 350 mm. 398 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 120‒129. Solenopsis forewings. 120, Solenopsis nr. nigella male. 121, Solenopsis sp. “thief ant” gyne. 122, S. gensterblumi gyne. 123, S. globularia littoralis gyne. 124, S. picta gyne. 125, S. picta male. 126, S. abdita gyne. 127, S. tennesseensis male. 128, S. abdita male. 129, S. carolinensis gyne, scale = 350 mm. VOLUME 120, NUMBER 2 399

Figs. 130‒135. Solenopsis major workers. 130, Mesosoma of S. metallica sp. nov., lateral view. 131, Head of S. metallica sp. nov., dorsal view. 132, Mesosoma of S. interrupta, lateral view. 133, Head of S. interrupta, dorsal view. 134, Mesosoma of S. invicta, lateral view. 135, Head of S. invicta, dorsal view. 400 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 136‒141. Solenopsis major workers. 136, Mesosoma of S. macdonaghi, lateral view. 137, Head of S. macdonaghi, dorsal view. 138, Mesosoma of S. megergates, lateral view. 139, Head of S. megergates, dorsal view. 140, Mesosoma of S. pusillignis, lateral view. 141, Head of S. pusillignis, dorsal view. VOLUME 120, NUMBER 2 401

Figs. 142‒147. Solenopsis major workers. 142, Mesosoma of S. quinquecuspis, lateral view. 143, Head of S. quinquecuspis, dorsal view. 144, Mesosoma of S. richteri, lateral view. 145, Head of S. richteri, dorsal view. 146, Mesosoma of S. saevissima, lateral view. 147, Head of S. saevissima, dorsal view. 402 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 148‒151. Solenopsis larval structures. 148, Head capsule, S. metallica sp. nov., dorsal, scale = 46 mm. 149, Mandible, S. metallica sp. nov., scale = 18 mm. 150, Bifid setae on head capsule, S. metallica sp. nov., dorsal, scale = 18 mm. 151, Head capsule, S. metallica sp. nov., dorsal, scale = 18 mm. VOLUME 120, NUMBER 2 403

Figs. 152‒159. Solenopsis larval structures. 152, Head capsule, S. interrupta, dorsal, scale = 46 mm. 153, Bifid setae on body, S. interrupta, dorsal, scale = 18 mm. 154, Mandible, S. interrupta, dorsal, scale = 18 mm. 155, Head capsule, S. saevissima, dorsal, scale = 46 mm. 156, Denticulate setae on body, S. saevissima, dorsal, scale = 46 mm. 157, Head capsule, S. interrupta, dorsal. 158, Maxillary palpus and galea, S. invicta, lateral. 159, Antennal setae, S. pusillignis, dorsal. 404 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 160‒169. Solenopsis larval structures. 160, Head capsule of S. invicta, dorsal view, scale = 46 mm. 161, Bifid setae on head capsule of S. invicta, scale = 18 mm. 162, Head capsule of S. invicta, dorsal view. 163, Head capsule of S. invicta, lateral view. 164, S. invicta, lateral view. 165, Head capsule of S. macdonaghi,dorsalview,scale= 46 mm. 166, Bifid setae on body of S. macdonaghi,dorsalview,scale= 18 mm. 167, Setae on head capsule of S. macdonaghi, dorsal view, scale = 18 mm. 168, Mandible of S. macdonaghi, dorsal view, scale = 46 mm. 169, Head capsule of S. macdonaghi, dorsal view. VOLUME 120, NUMBER 2 405

Figs. 170‒177. Solenopsis larval structures. 170, Head capsule of S. megergates, dorsal view, scale = 46 mm. 171, Antenna of S. megergates, dorsal view, scale = 18 mm. 172, Mandible of S. megergates, dorsal view, scale = 18 mm. 173, Head capsule of S. megergates, dorsal view. 174, Head capsule of S. megergates, lateral view. 175, S. megergates, lateral view. 176, Head capsule of S. quinquecuspis, dorsal view. 177, Head capsule of S. saevissima, dorsal view. 406 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 178‒185. Solenopsis larval structures. 178, Head capsule of S. quinquecuspis, dorsal view, scale = 46 mm. 179, Mandible of S. quinquecuspis, dorsal view, scale = 18 mm. 180, Bifid setae on head capsule of S. quinquecuspis, lateral view, scale = 18 mm. 181, Simple setae on head capsule of S. quinquecuspis, lateral view, scale = 18 mm. 182, Head capsule of S. saevissima, dorsal view, scale = 46 mm. 183, Head capsule of S. saevissima, lateral view. 184, S. saevissima, lateral view. 185, Head capsule of S. richteri, dorsal view. VOLUME 120, NUMBER 2 407

Figs. 186‒194. Solenopsis larval structures. 186, Multi-branched setae on body of Solenopsis richteri, lateral view, scale = 18 mm. 187, Multi-branched setae on body of S. richteri, lateral view, scale = 18 mm. 188, Mandible of S. richteri, lateral view, scale = 46 mm. 189, Head capsule of S. richteri,dorsal view, scale = 46 mm. 190, Head capsule of S. pusillignis, dorsal view, scale = 46 mm. 191, Bifid setae on head capsule of S. pusillignis, lateral view, scale = 18 mm. 192, Mandible of S. pusillignis, lateral view, scale = 46 mm. 193, Head capsule of S. pusillignis, dorsal view. 194, Head capsule of S. pusillignis, lateral view. 408 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Figs. 195‒200. Solenopsis daguerrei. 195, Head of gyne, dorsal view. 196, Head and pronotum of gyne. 197, Mandible of gyne, dorsal view. 198, Propodeum of gyne, lateral view. 199, Head of male, dorsal view. 200, Scape, pedicel and flagellomeres 1‒2 of male, lateral view, scale = 0.14 mm. VOLUME 120, NUMBER 2 409

Fig. 201. Distribution of Solenopsis electra, S. metallica sp. nov., S. saevissima, and S. weyrauchi. Evolutionarily independent lineages (sensu Ross et al. 2010) of S. saevissima are also indicated. Col- lection localities from the collecting trips presented here are indicated by circles (◯). Type localities are indicated by triangles (D), other reliable collection localities (Trager 1991) are indicated by squares (u). 410 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON

Fig. 202. Distribution of Solenopsis interrupta, S. macdonaghi, S. megergates, S. pythia, and S. quinquecuspis. Collection localities from the collecting trips presented here are indicated by circles (◯). Type localities are indicated by triangles (D), other reliable collection localities (Trager 1991) are indicated by squares (u). VOLUME 120, NUMBER 2 411

Fig. 203. Distribution of Solenopsis daguerrei, S. invicta, S. pusillignis, and S. richteri. Collection localities from the collecting trips presented here are indicated by circles (◯). Type localities are in- dicated by triangles (D).

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