TAES 142: 167-213 RESEARCH ARTICLE ISSO 0002-8320 http://taes.entomology-aes.org/

Hydrochidae (Coleoptera) of Mississippi

Reese J. Worthington1, John L. Hellman2, Paul K. Lago 1

1Department of Biology, University of Mississippi, University, MS 38677. Corresponding author email: [email protected]. 2Department of Entomology, University of Maryland, College Park, MD 20742.

ABSTRACT

Mississippi Hydrochidae are poorly known. In this paper, we attempt to untangle some of the taxonomic difficulties caused by recent dubious works of D. Makhan and to validate an undescribed species from previously unpublished research. The 12 species occurring in Mississippi are reviewed and one new species, H. falsus Hellman sp.n., is described. Six new synonymies are established as follows: Hydrochus hanoewanti Makhan, 1994 is a junior synonym of Hydrochus rugosus Mulsant, 1844; Hydrochus monishi Makhan, 1995 is a junior synonym of Hydrochus foveatus Haldeman, 1852; Hydrochus equicarinatus Blatchley, 1928 is a junior synonym of Hydrochus simplex LeConte, 1855; Hydrochus daviniaae Makhan, 1995 is a junior synonym of Hydrochus vagus LeConte, 1851; Hydrochus bakkeri Makhan, 1995 is a junior synonym of Hydrochus obscurus Sharp, 1882; and Hydrochus soesae (Makhan), 2004 is a junior synonym of Hydrochus scabratus Mulsant, 1844. Hydrochus inaequalis LeConte, 1855 is removed from synonymy with Hydrochus foveatus Haldeman, 1852 and resurrected as a proper species. Neotypes are designated for H. rugosus Mulsant, 1844, H. rufipes Melsheimer, 1844, and H. scabratus Mulsant, 1844. A lectotype is designated for H. foveatus Haldeman, 1852. Species descriptions, illustrations of male genitalia, distribution maps and a key to species are presented. Additional notes on Makhan species and holotypes, including unavailable types, are provided. Key words: Hydrochidae, Hydrochus, Mississippi, taxonomy

INTRODUCTION professionalism is well known and has extended well beyond Hydrochus into several other groups Taxonomy of North American Hydrochidae, (Hansen 1998, 1999; Jäch 2000; Short and Hebauer containing only the nearly cosmopolitan genus 2006; Steiner et al. 2003; Oliva 2000; Watts 1999). Hydrochus, has been in a state of disarray for Taxonomic confusion within the genus has been nearly a century. This was true during the first part created primarily by great variation in external of the 1900’s primarily because species descriptions features, eg. color, size and surface sculpturing, were poorly written, keys were not available or which is often readily apparent within individual not diagnostic, types were either inaccessible populations of the various species. In most cases, or ignored by authors, and the importance of positive species identification requires examination male genitalia in diagnosing species was not of male genitalia, while females can, generally, be yet recognized. More recently, the problem was identified only by association with males from the exacerbated by the various works of Dewanand same locality or collecting event. Makhan involving North American members of In 1975, Hellman produced a comprehensive the genus (Makhan 1994, 1995a, 1995b, 1996, study of the North American members of the 2000, 2001, 2004a, 2004b, 2005). Makhan’s genus Hydrochus as a dissertation project. Prior continuous application of poor taxonomic concepts, to this work, 31 species had been described from intellectual misappropriation, and lack of scientific the Western Hemisphere. As a consequence of his

Publication date: 28 October 2016 urn:lsid:zoobank.org:pub:D4181AC8-66A6-4007-A139-8A2C872803E7 168 hydrochidae of Mississippi study, 50 species were recognized as occurring in rivers and streams. Though there are numerous North America, 28 of which were considered to be small to large man-made impoundments, the state new, and six synonyms were established. While lacks natural lakes aside from oxbows formed the production of the dissertation represented a by the remnants of old river channels. The state significant advancement inHydrochus taxonomy, lies principally within the Gulf-Atlantic Coastal the work was never published. Names ascribed (Eastern) Plain physiographic region of North to new species were unavailable for taxonomic America, with only the extreme northeastern purposes and the synonyms never recognized. corner exhibiting an Appalachian influence. Eleven Some of the new species have been subsequently physiographic regions are represented in the described by others (Smetana 1988; Makhan 1994, state (Figure 1) (Cross et. al. 1974; ESRI 2011; 1995a, 1995b, 1996, 2000, 2001, 2004a, 2004b, Lowe 1915; Mississippi Dept. of Environmental 2005). Several of Hellman’s undescribed species Quality 2013; U.S. Dept. of Commerce 2014), have received numerical designations in keys to and are referenced in our discussions of species Florida (Epler 1996, 2010) and South Carolina distributions. See Testa and Lago (1994) for a (Ciegler 2003) water beetles. Prior to the current more detailed discussion of aquatic habitats and work, Hydrochus comprised 34 described species in descriptions of physiographic regions. the United States and Canada, with 16 occurring in Specimens Examined — The diversity of the southeastern United States. As now configured, aquatic habitats in Mississippi has spawned the genus comprises 31 described species in the equally diverse surveys of aquatic arthropods in United States and Canada, with 16 occurring in the the state, most of which occurred during the past southeastern United States. 40 years. All of these surveys, particularly for The stimulus for this work was a rather large Trichoptera, have involved many hours of light- collection of specimens available through previous trapping throughout the state and the bycatch of research and collecting efforts in and around aquatic specimens from these activities has resulted in habitats throughout Mississippi. Preliminary numerous opportunities to explore portions of our examination of specimens revealed significant fauna not specifically targeted by the collecting problems with available keys and a few obviously activities. Such is the case with Hydrochus. In new species, as well as species fitting some of total, 1,019 specimens were examined during Hellman’s (1975) descriptions. Problems with the this study, including many collected by the work of Makhan were similarly apparent. authors, as well as specimens from University of In this study, our first goal was to validate one Mississippi Insect Collection (UMIC), Auburn new species set forth in Hellman’s dissertation. University Entomology Collection (AUEC), and the Secondly, by examination and imaging of all related Mississippi Entomological Museum (Mississippi type materials, we hope to bring some stability State University, Mississippi, MEM). Holotypes and to Hydrochus taxonomy through verification paratypes were borrowed from the Illinois Natural of species ambiguously described by Makhan. History Survey Insect Collection; the Natural Lastly, we review the Hydrochus found in the state History Museum, London; the Museum of Natural of Mississippi, provide a key to species, record History, Berlin; and Museum of Natural History, available biological data, and note seasonal and Vienna. geographic distributions of the species occurring Photographs were taken using a Leica here. DFC digital camera mounted on a Leica Z16 Macroscope. Images were stacked using Leica MATERIALS AND METHODS Application Suite vs. 4.1 with an Automontage module. All measurements were made using a Wild Study Area — A great diversity of aquatic M5 stereomicroscope with a Wild MMS235 digital habitats occurs within Mississippi, ranging from length measuring set. small to large swamp systems, bogs, seeps, Male genitalia were extracted by placing woodland ponds, flowing springs, and myriad specimens in warm, distilled water for one minute. worthington et al. 169

Figure 1. Physiographic regions of Mississippi. I= Coastal Meadows, II= Southern Pine Hills, III= Jackson Prairie, IV= Loess Hills, V= Alluvial Plain, VI=North-Central Hills, VII= Flatwoods, VIII= Pontotoc Ridge, IX= Black Prairie, X= Tombigbee-Tennessee River Hills, XI= Paleozoic Bottoms.

Insect pins (Size 00) with hooked tips were used elongate in form, with protuberant eyes; antennae to open the pygidium and separate the genitalia with seven antennomeres, three antennomeres distal from the surrounding connective tissue. Genitalia to cupule densely pubescent; maxillary palpi with were preserved in glycerine in polyethylene plastic four palpomeres, labial palpi with three palpomeres; microvials (10 mm long x 4 mm diameter), which pronotum narrowed at base, always narrower than were mounted below specimens on the insect pin. base of elytra. Venter with five visible abdominal The authors would like to stress the importance of sternites, pubescent, apex of fifth visible sternite preserving male genitalia in glycerine rather than with a small non-hydrofuge pubescent plaque, basal applying genitalia to cards using adhesive. Adhesive portion of plaque bearing numerous stout setae in badly distorts the genitalia, and carded genitalia various patterns, terminal portion appearing thin, of all specimens examined during this study were hyaline and smooth. Male genitalia trilobed with removed and stored in glycerine as described above, parameres articulating with a basal piece. Tarsi including those of types. with bisetose empodium. Eggs are laid singly or in groups, all eggs surrounded with a silken sac Family Hydrochidae and cemented to various submerged materials. Family Hydrochidae Thomson Larvae with mandible possessing large retinaculum and small mola; stipes with rudimentary lacinia; Hydrochidae Thomson, 1860, p. 75. palpiger without galea; abdomen parallel sided with Type genus: Hydrochus Leach, 1817, p.75, by eight fully developed segments; terminal segments monotypy. forming a stigmatic atrium.

Small to moderate beetles, elongate to sub- 170 hydrochidae of Mississippi

Genus Hydrochus Leach (1817) basolateral foveae near posterolateral angles. Prosternum very irregularly foveate and moderately Type species: Elophorus elongatus Fabricius, densely punctate; venter completely covered with a 1792 (=Silpha elongata Schaller, 1783), by subsequent dense hydrofuge pubescence, including the coxae, designation by Curtis 1831, p. 359. trochanters and extending a short distance onto base of femora. Coxal cavities closed behind. The Members of this genus superficially resemble mesosternum coarsely punctate, irregularly foveate members of the hydrophiloid genus Helophorus, with hydrofuge pubescence as on the prosternum. but upon closer examination, species of Hydrochus Mesocoxae divided on the midline by a carinate differ in having the pronotum more or less equally posterior mesosternal process that frequently as long as wide with the base much narrower than appears posteriorly continuous with apex of the elytral base. The pronotal disc in Hydrochus species similarly carinate metasternal process. Metasternum is rugose, deeply and coarsely punctate and foveate. convex medially, very unevenly and irregularly Helophorus species have the pronotum much wider foveate, coarsely punctate and with pubescence than long and with five distinct longitudinal sulci on similar to that of the prosternum and mesosternum. the disc. Legs generally unmodified. All tarsi bear a pair of Mississippi species of Hydrochus range in large, strong curved claws. length from 2.2 mm to 6.1 mm. Elytra strongly convex, elongate to sub- Head as long as wide and with very large, elongate, occasionally very broad. Humeral rounded protuberant eyes. Dorsally, clypeus large, umbones distinct, frequently elevated. Each elytron convex and densely punctate; epistomal sulcus has ten rows of coarse, deep, regular punctures. either lacking or distinct. Mid-occipital region of The intervals usually vary from costate to flat, head constricted, more narrow than interocular occasionally callosed or tuberculate. Each interval region. Maxillary palpi with four palpomeres, basal bears a series of very fine setae. Intervals typically palpomere very small and terminal palpomere vary in degree of elevation. largest and swollen subapically. Labial palpi with Abdomen with five sternites fully visible, first three palpomeres, the first two very short and with a broad medial and two shorter sub-lateral together subequal in length to ultimate palpomere. longitudinal carinae of varying elevations; carinae Antennae subequal in length to maxillary palpi. coalesce near base, with a broad, transverse, Mentum pentagonal with disc often depressed or irregularly raised area. Remaining sterna broadly foveate medially; submentum much broader than carinate or raised to varying degrees across the long, rectangular, with disc flat or foveate. sternum along the anterior margin. Thorax with pronotum convex, usually as The male genitalia are trilobed, characterized long as greatest width, widest in apical half, and by a phallobase, median lobe (aedeagus), and distinctly narrowed basally; anterior margin may paired, symmetrical lateral lobes (parameres). be arcuate, straight or recurved just behind the eyes Shape of the aedeagus and parameres varies so that anterolateral angles are anteriorly produced; greatly between species, but appears uniform posterior margin arcuate; disc generally coarsely, within species, thus both structures are useful densely punctate or granulate-punctate; pronotal diagnostically. The shape of the apicoventral space disc exhibits various stages of foveal development, of the phallobase shows less variation between ranging from nearly obscured to having nine species, but can be equally diagnostic. prominent foveae. Foveae arranged across the disc The male genitalia of Hydrochus are of three in three series: anterior series with two small or basic types. The form most commonly seen is indistinct anterolateral foveae; medial series with a characterized by an elongate phallobase, median median fovea and two adjacent mediolateral foveae lobe, and paired, symmetrical lateral lobes. The near lateral margins; third, or posterior, series basoventral opening of the phallobase, which with four foveae, two elongate basomedial foveae receives the ejaculatory duct, is terminally located. on each side of midline and two much smaller The second genital form is limited to worthington et al. 171

Hydrochus species in North and South America third; parameres parallel when viewed dorsally, and bears a set of accessory lateral lobes. These never diverging or converging to the point accessory lobes, called pseudoparameres, are of contact apically; parameres straight when weakly sclerotized membranous sheets appressed viewed laterally; size larger, 3.4–5.6 mm . . to a portion of the ventral and lateral surface of the ...... H. callosus parameres. Pseudoparameres attach at the junction 2’. Male parameres gradually tapering; parameres of the phallobase and parameres. The shape and diverging apically or converging to the point size of the pseudoparameres usually parallels of contact when viewed dorsally; parameres that of the parameres. The presence or absence of curved when viewed laterally; size smaller, pseudoparameres is more useful diagnostically than 2.6–3.9 mm ...... 3 the length, size or shape of these structures. 3. Elytral apices slightly produced with sutural The third genital form is characteristic of the angles nearly acute; incurved portion of male H. scabratus group of North America and the H. parameres in lateral view with sub-apical notch brevis group of northern Europe. In this form, the ...... H. jiawanae parameres are expanded basally and the phallobase 3’. Elytral apices at sutural angles rounded; is two to five times the length of the parameres. The incurved portion of male parameres in lateral basoventral opening that receives the ejactulatory view lacking sub-apical notch, entirely smooth duct in the phallobase is not terminal as in the other ...... H. falsus n. sp. forms, but is subapical. The apex of the phallobase is closed and typically rounded. The aedeagus is 4. Length 4.8–6.1 mm; phallobase approximately generally half the length of the parameres and rarely equal to length of parameres; parameres, overlaps the anterior edge of the phallobase. lateral view, ventral surface flat, dorsal Epler (1996, 2010) and Oliva (1996) surface equal in elevation to dorsal surface of discuss membranous apical ridges, lamella and phallobase, parameres beyond junction with lobes present on the aedeagus of some species. phallobase raised and rounded one-half length Epler (1996, 2010) noted the exclusion of these of parameres, apical half of parameres tapering structures from genitalia figures in Hellman (1975). gradually to apex; apex blunted, straight; Examination of large series of several species aedeagus extending seven-eighths length of known to exhibit the structures in question has parameres; aedeagus, lateral view, ventral revealed great variability in size and shape of these surface flat, dorsal surface with three swellings membranous structures. Individuals of the same decreasing in size towards apex, two apical species from the same series may lack or possess swellings extending above dorsal surface of the structures. This has led to the conclusion that parameres, apex weakly acuminate; epipleura these structures represent the internal sac of the impunctate and smooth . . . . .H. rugosus aedeagus in various states. As they are variable in 4’. Length <4.6 mm; genitalia not as figured; size and shape, we have chosen to exclude them as epipleura bearing some punctation . . . . 5 diagnostic characters for identification. 5. Male genitalia with phallobase much shorter Key to the species of Mississippi Hydrochus than parameres ...... 6 5’. Male genitalia with phallobase longer or 1. Epicranial suture absent, if present epicranial subequal in length to parameres . . . . . 8 stem present, lateral arms absent; two large pits evident in interocular space; epipleura 6. In lateral view, aedeagus nearly reaching apex impunctate ...... 2 of parameres, phallobase two-thirds length 1’. Epicranial suture present; interocular space of parameres; epipleura moderately, coarsely lacking pits; epipleura variable ...... 4 punctate, punctures becoming indistinct in apical fourth ...... H. simplex 2. Male parameres abruptly narrowing beyond basal 6’. In lateral view, phallobase approximately three- 172 hydrochidae of Mississippi

fourths length of parameres; epipleura punctate moderately, coarsely punctate on basal three- throughout ...... 7 fourths, punctures moderately deep near base then gradually shallower until disappearing on 7. In lateral view, aedeagus approximately two- apical half, punctures absent beyond apical half thirds length of parameres with submedial, ...... H. schereri dorsal swelling; epipleural punctures occasionally coalescing ...... H. pajnii Hydrochus callosus LeConte, 1855 7’. In lateral view, aedeagus extending nearly to apex of parameres and lacking submedial, Hydrochus callosus LeConte, 1855: 359. dorsal swelling; epipleural punctures arranged Hydrochous callosus LeConte; Zaitzev, 1908a: 334. in a single series, not coalescing ...... H. excavatus Description — Male--Very robust, sub- elongate, very strongly convex; maximum length 8. In lateral view, aedeagus lacking swelling or 4.4 mm, maximum width 1.8 mm; maximum width strong undulation on dorsal margin . . . . 9 of head across eyes 1.0 mm, minimum interocular 8’. In lateral view, aedeagus with swelling or distance 0.6 mm; maximum length of pronotum 1.0 strong undulation on dorsal margin . . . . 10 mm, maximum width 1.2 mm, minimum width at base 1.0 mm; maximum length of elytra 3.0 mm. 9. In dorsal view, apicoventral space of phallobase Dorsum dull, head piceous, pronotum and triangular in shape, dorsal margin of aedeagus elytra dark reddish brown; however, entire dorsum straight; epipleura shallowly, finely punctate on with variably shining metallic green, gray, blue- basal three-fourths ...... H. rufipes gray, and brassy reflections obscuring nearly all 9’. In dorsal view, apicoventral space of phallobase ground color. Mentum and submentum shiny not triangular in shape, space occurs across full rufopiceous with dull metallic reflections similar to width of phallobase, dorsal margin of aedeagus those of dorsum. Antennae and palpi reddish brown narrowing toward apex; epipleural punctures with apex of ultimate maxillary palpomere slightly large, irregular, and shallow from base to apical darkened or piceous. Legs reddish brown with fourth ...... H. neosquamifer tibiofemoral joints and apex of ultimate tarsomeres dark brown or piceous; ground color of femora and 10. In lateral view, ventral surface of parameres tibiae somewhat obscured by dull metallic green flattened; in dorsal view, parameres widening reflections. Head across eyes subequal to width into rounded projections, then tapering to apex; of pronotum; lateral margins of clypeus slightly epipleura coarsely punctate on basal half, then raised, disc gradually, shallowly, broadly, ridged between middle and apical fourth punctures on midline, ridge more broadly expanded basally; shallower and smaller, absent in apical fourth… clypeal punctures moderately large, similar to those ...... H. jaechi on interocular region, deep, dense, most irregularly 10’. In lateral view, ventral surface of parameres spaced in close groups of twos, threes, or fours and concave; in dorsal view, parameres tapering to separated within groups by less than one-third width apex, but lacking rounded projections . . 11 of a puncture; epistomal sulcus lacking; interocular region very scabrous; midcranial depression 11. In lateral view, swellings of dorsal margin of replaced by a broad, elevated ridge which separates aedeagus subequal in size, not deeply incised and extends length of submedial depressions; dorsally; epipleura irregularly punctate… . . submedial interocular depressions elongate, deeply ...... H. inaequalis foveate, coarsely punctate, punctures scattered, 11’. In lateral view, swellings of dorsal margin of occasionally coalesced, and generally closer than on aedeagus varying greatly in size, sub-medial surrounding elevated areas of disc; most punctures swelling larger, aedeagus deeply incised coarse, same density but larger than those on base of apically of sub-medial swelling; epipleura clypeus; elevated areas between eyes and submedial worthington et al. 173

depression unevenly but strongly elevated, width of a puncture, punctures in apical third nearly tuberculate; mid-occipital region between and near lateral margin smaller and denser; fine posterolateral margin of eyes not constricted but setigerous punctures of intervals arranged on each broadly raised and anteriorly continuous with ridge interval in single series except where doubled on on midline separating submedial depressions; elevated portions of interval, setigerous punctures mentum finely, densely punctate, with nearly denser in apical fourth and along sutural intervals; entire discal surface strongly foveate medially; sutural interval in basal half flat, twice width of submentum very minutely and sparsely punctate other intervals, becoming gradually wider and with only two very small, deep foveae on disc. costate in apical third; remaining intervals broad, Pronotum very strongly, unevenly convex, separated by nearly twice their width, most appear wider than long, widest in apical third; anterior flat and uniform in width except as follows: nd2 , margin straight; lateral margins slightly inflexed 3rd, 6th, 7th, and 8th intervals slightly raised in basal in apical half; punctation on inflexed surface same fourth, with basal third of 3rd interval subcostate as on dorsum; sides viewed from above, round, , 2nd and 3rd intervals slightly raised from just very strongly sinuate with apical half slightly before middle to the beginning of the apical third arcuate, basal half incurved, strongly narrowed where 2nd, 3rd, and to a lesser degree 4th intervals to base behind middle; posterior margin strongly become strongly thickened and raised together arcuate medially; disc rugose; outline of midline (callused), the three calli coalesce and together in lateral view very prominently raised in apical form an obliquely transverse prominent callus with fourth just anterior to median fovea, then broadly 3rd interval raised higher than any other interval; depressed before middle, basal half slightly raised 2nd interval in apical fourth only slightly raised near middle then flattened on basal third; punctures from behind callus to margin; 4th interval in apical very dense, very deep, coarse, irregularly spaced, fourth briefly costate at midlength between callus most separated by one-half to one-third width on beginning of apical third and apical margin of diameter of a single puncture, denser and finer elytron; 6th interval briefly and slightly costate just toward anterolateral margins; middle of median anterior to the adjacent callus on 4th interval; 8th fovea distinctly impunctate, smooth. Anterolateral interval unevenly raised, and only slightly costate foveae indistinct; median fovea large, elongate, near middle, costa on 8th interval nearly twice nearly twice as long as wide and equal to one-half length but not elevated above costa of 6th interval; length of pronotum at midline, foveal margins epipleuron impunctate, smooth, basal third slightly anterolaterally shallow, interrupted, basally impressed on midline. mostly indistinct and open to basomedial foveae; Male genitalia. Figure 2. Entire genital mediolateral foveae round, moderately deep, structure dorso-ventrally compressed. Phallobase nearly equal to one-third length of median fovea; greater than two times length of parameres; apex basomedial fovea very feeble; basolateral foveae round, closed; widest medially, at narrowest point small, deep, larger and more distinctly developed equal to width of parameres; basoventral opening than anterolateral foveae; midline of pronotum subapical. Apicoventral space widest at junction of slightly impressed just anterior to scutellum. parameres and phallobase, narrowing to acuminate Venter with posterior mesosternal process point. Parameres symmetrical, widest at base, between mesocoxal cavities sharply carinate and anterior two-thirds straight-sided, greatly narrowed; elevated slightly above level of metasternal carina. apices weakly deflexed. Aedeagus short, two-fifths Elytron strongly convex, sub-elongate with length of parameres; viewed laterally, constricted strongly deflexed sides; lateral margin medially medially with apex unevenly rounded; in dorsal explanate, and strongly arcuate behind middle to view, with two basal projections visible posterior to apical fourth, apical fourth constricted subapically; parameres in apicoventral space of phallobase. apex slightly angulate behind 4th interval, then Female — Indistinguishable from males. abruptly rounded to suture; serial punctures large, Variation — The specimens vary in length from deep, those on disc separated by slightly less than 3.4–5.6 mm and in width from 1.7–2.3 mm. The 174 hydrochidae of Mississippi metallic colors vary from a bright brassy golden interocular distance 0.6 mm; maximum length green to dull green, gray-green or lead gray. The of pronotum 0.8 mm, maximum width 0.8 mm, elytral intervals show considerable variation in the minimum width near base 0.75 mm; maximum degree of reflected coloration. length of elytra 2.3 mm. Distribution — Hydrochus callosus is Dorsum dull, head piceous; pronotum and distributed from Florida and Georgia, and west to elytra brown; however, various metallic green to Texas. According to Young (1954), this species is gray-green reflections obscure most of ground color. abundant throughout the Apalachicola lowlands of Mentum and submentum rufopiceous with metallic northern Florida. In Mississippi, H. callosus, occurs green and violet puncture reflections. Antennae and in most physiographic regions, but is apparently palpi reddish brown with only tibiofemoral joints absent from the regions of higher elevation in the and apex of ultimate tarsomeres piceous. northeastern corner of the state (Fig. 3). Head across eyes equal to width of pronotum; Material Examined — We have examined 46 clypeus rugose, punctures very dense, moderately specimens from Mississippi localities, including: coarse, most punctures slightly smaller than on Amite Co. 7 mi ENE Liberty [UMIC], Clarke Co. interocular region; with fine setae obscured by 1.5 mi N Enterprise [UMIC], George Co. 12 mi metallic reflections; epistomal sulcus fine near SW Lucedale, Pascagoula WMA [UMIC], Hancock lateral margins, gradually broadened and deeply Co. 4 mi NW Kiln [UMIC], Lamar Co., Lauderdale impressed toward middle, punctures within medial Co. 3 mi S Arundel [UMIC], Noxubee Co. 10 mi epistomal impression frequently coalesced and W Macon [UMIC], Stone Co. UM Forest Lands, often obscuring sulcus; interocular region rugose, Henley Park; 2 mi N Perkinston; T4S-R1W-Sec. 6 gradually, irregularly raised behind epistomal [UMIC], Tallahatchie Co. 5 mi WNW Charleston sulcus to vertex; midcranial depression moderately, [UMIC], and Tate Co. 2 mi N Coldwater [UMIC]. deeply sulcate, coarsely punctate, punctures nearly Seasonal Distribution —Mid-April through coalesced; submedial interocular depressions very mid-August. irregular, shallow; elevated areas at vertex smooth Diagnosis — Externally, H. callosus is most to irregularly and more sparsely punctate than on similar to H. falsus and H. jiawanae; however, H. surrounding integument; punctures moderately callosus can be distinguished from these species by large, very irregularly spaced, with several having both enlarged elytral calli and a greater body coalesced or nearly coalesced pairs scattered over width. The male genitalia (Fig. 2) narrow abruptly discal surface; setae as on clypeus; mid-occipital at the basal third of the parameres, while those of region broadly constricted between posterolateral H. falsus (Fig. 20) and H. jiawanae (Fig. 23) taper margin of eyes. Mentum finely, very densely gradually. punctate, basal two-thirds of disc deeply foveate Biology — Hydrochus callosus may be medially; submentum very sparsely punctate, found in lentic habitats (Epler 2010), as well as in punctures slightly denser along lateral margin, disc slow flowing streams (Young 1954). Mississippi nearly completely covered by two very large, deep specimens were collected near swamps, woodland foveae. ponds and moderately large rivers, some sandy, Pronotum strongly convex, slightly wider others with muddy bottoms. than long, widest in apical third; anterior margin straight; lateral margins very strongly and narrowly Hydrochus excavatus LeConte, 1855 inflexed; inflexed surface moderately coarsely punctate without the rugose interspaces typical of Hydrochus excavatus LeConte 1855: 360. the dorsal surface; sides of pronotum viewed from Hydrochous excavatus LeConte; Zaitzev, 1908a: 334. above angulate, crenate, teeth coarse and close, very shallowly sinuate in outline with apical half Description — Male--Elongate; maximum parallel, then slightly incurved behind middle and length 3.3 mm, maximum width 1.3 mm, maximum moderately narrowed to base; posterior margin width of head across eyes 0.8 mm, minimum arcuate medially; punctures moderately coarse, worthington et al. 175

irregularly spaced and generally separated by one- in a single series, shallow and somewhat more half width of puncture, denser and slightly finer irregularly spaced than on dorsum. toward lateral margins; punctures within median Male genitalia. Figure 4. Phallobase three- fovea less dense than on surrounding discal surface; fourths length of parameres; apex round; widest elevated areas of disc here and there with very at junction with parameres, tapering to apex; small sparsely punctate or smooth areas; discal phallobase at junction with parameres equal to surface anterolaterally becoming slightly granulate, maximum width of parameres; basoventral opening granules generally small, not very high or well terminal. Apicoventral space sagittate, widest formed. Anterolateral and basolateral foveae anteriorly narrowed to acuminate angulation moderately deep, rounded, median fovea equal to posteriorly. Parameres symmetrical, widest at base, nearly one-fourth length of pronotum at midline; tapering to apex, sinuate in dorsal view; in lateral basomedial foveae much more irregular in form view, tapering toward apex, ventral surface nearly than others, moderately deep, slightly elongate and flat (weakly concave) to apex; apices straight. convergent basally. Aedeagus five-sixths length of parameres; in lateral Elytron strongly convex, elongate; lateral view, forked in apical fourth, apex acuminate; margin narrowly explanate medially, moderately widest at junction with parameres and phallobase, arcuate medially to apical third, then feebly tapering to apex. Apicoventral space of phallobase constricted subapically; apex slightly angulate receiving two dorsal projections of aedeagus behind 4th interval and then abruptly rounded to extending two-thirds length of apicoventral space. suture; serial punctures very coarse, deep, those Female — Indistinguishable from males. on disc separated by one-half width of a puncture, Variation — Specimens vary in length from those in apical third becoming smaller and denser; 2.8–3.3 mm and in width from 1.0–1.3 mm. sutural interval near base raised, and wider than Pronotal foveae vary from moderately deep to others, posteriorly becoming gradually, but only shallow. Those specimens exhibiting more shallow slightly, wider and subcostate on apical third; foveae have less distinct elevations on the elytral remaining intervals on the elytron appear narrower intervals. than width of a serial puncture; several intervals Distribution — Hydrochus excavatus occurs are unequally raised and widened as follows: from New York south to Florida and as far west 2nd interval slightly costate on basal third, then as Louisiana and extends up the Mississippi River interrupted to midlength where again becoming valley into southern Illinois and Indiana. (Arnett slightly raised from behind middle to beginning 1983; Notman 1919, White et al. 1985). Hydrochus of the apical third; 3rd interval feebly raised near excavatus is found in the Southern Pine Hills (II), base, then interrupted, similar to 2nd interval, North-Central Hills (VI), Flatwoods (VII), Pontotoc and becoming moderately costate from behind Ridge (VIII), and Black Prairie (IX) regions of middle to beginning of the apical third; 4th interval Mississippi (Fig. 5). unequally raised in basal half with interval behind Material Examined — We have examined five basal fourth becoming slightly broadened and specimens from Mississippi localities, including: moderately costate to just before middle, interval Choctaw Co. 12.5 mi NNE Weir [UMIC], George then interrupted and flattened to where moderately Co. 12 mi SW Lucedale [UMIC], and Oktibbeha broadened and callused on beginning of apical Co. 3 mi W of Adaton, 33 ° 29’00”N, 88°58’13”W third, callus very prominent, high, much more [MEM]. elongate than wide; interval unevenly raised over Seasonal Distribution — Late June through most of its length, with a small, weak but distinct mid-August. costa near middle; 8th interval elevated like 6th Diagnosis — Hydrochus excavatus most interval, but with a small weak costa near middle; closely resembles H. inaequalis and H. pajnii; 7th interval near middle slightly sinuate and nearly however, H. excavatus possesses epipleural coalesced with small costa on 8thinterval; epipleuron punctation arranged in a single series, which moderately coarsely punctate, punctures arranged distinguished it from the others, which have 176 hydrochidae of Mississippi

coalescing epipleural punctures or irregular clypeus very rugose, punctures moderately coarse epipleural punctures. Additionally, H. excavatus can and very dense; coarser punctation with numerous be separated from H. pajnii by the slightly larger fine setae interspersed, most setae obscured by size and higher, broader callus of the 4th elytral the metallic reflections, epistomal sulcus fine interval of the latter. Due to variation between the near lateral margin, gradually broadened and species in size and prominence of the calli on the moderately impressed medially; interocular region 4th elytral interval, using this character might lead rugose, gradually, unevenly raised to vertex behind to misidentifications. The genitalia ofH. inaequalis epistomal sulcus; mid-cranial depression short, (Fig. 6) differ from those of H. pajnii (Fig. 26) deeply sulcate and coarsely punctate, punctures of and H. excavatus (Fig. 4) in having a concavity mixed sizes and coalesced; submedial interocular present on the ventral surface of the parameres, the depressions irregular, very shallow and with apex of the parameres decurved, and the aedeagus slightly closer punctation than on adjacent discal with an extension below the ventral surface of the elevated areas, which are slightly less densely parameres. Hydrochus pajnii can be separated by punctate; punctures mixed, most moderately large the extension of the aedeagus above the dorsal and irregularly spaced; setae same as on clypeus; surface of the parameres and a large swelling in the mid-occipital region broadly, moderately deeply basal half of the aedeagus. Hydrochus excavatus constricted between posterolateral margin of eyes. lacks the large dorsal swellings of the aedeagus Mentum finely, densely punctate, disc moderately seen in H. pajnii and the aedeagus does not extend deeply foveate medially in basal two-thirds, beyond the parameres ventrally, dorsally, or submentum sparsely, finely punctate, with disc apically. nearly completely covered by two large foveae. Biology — Specimens have been collected at Pronotum rugose, convex, slightly wider black light or ultraviolet light near ponds, streams, than long, widest at anterolateral angles; anterior and pools (Ciegler 2003). Mississippi specimens margin straight; lateral margins narrowly inflexed; were collected from a small stream and in black sculpture on inflexed surface same as on dorsum; light traps set near a large river and a marsh. sides of pronotum angulate, sinuate in outline with apical half nearly parallel sided, basal half slightly Hydrochus inaequalis LeConte, 1855 incurved and narrowed to base; posterior margin arcuate medially, punctures dense, coarse, deep, Hydrochus inaequalis LeConte 1855: 359. nearly equal in size, irregularly spaced, those on middle of median fovea slightly less dense than Description — Male—Elongate, moderate on surrounding discal surface. Anterolateral and size; maximum length 2.6 mm, maximum width 1.2 posterolateral foveae very shallow; median fovea mm, maximum width of head across eyes 0.8 mm, moderately deep, rounded and approximately equal minimum interocular distance 0.4 mm, maximum to one-third pronotal length; mediolateral foveae length of pronotum 0.7 mm, maximum width 0.8 similar to median fovea; basomedial foveae slightly mm, minimum width near base 0.6 mm; maximum smaller and shallower than median fovea, and length of elytra 1.9 mm. slightly convergent near base. Dorsum shiny with mixed metallic green, Elytron elongate, moderately convex; lateral brassy and scattered purple metallic reflections; margin feebly explanate medially then moderately ground color mostly hidden by reflections, but arcuate behind middle to apex; apex abruptly head piceous; pronotum and elytra brown. Mentum rounded to suture; serial punctures large, deep, and submentum rufopiceous with scattered green those on disc separated by nearly one-third width and purple reflections. Antennae and palpi reddish of a puncture, punctures in apical third gradually brown with only apex of ultimate maxillary smaller and much closer; sutural interval in palpomere piceous. Legs reddish brown with basal half flat and only slightly wider than other tibiofemoral joints and apex of tarsi piceous. intervals, posteriorly becoming gradually wider Head across eyes equal to width of pronotum; and subcostate on apical third, remaining intervals worthington et al. 177

appear narrow, separated by nearly twice their west as Louisiana, with limited records through width, with several unequally elevated as follows: the Mississippi River Valley north to Missouri 2nd interval narrowly costate on basal third, then and Indiana (Arnett 1983, White et al. 1985). interrupted and flattened behind costa to near mid- This species is widely distributed in Mississippi, length where becoming briefly costate to beginning occurring in the Coastal Meadows (I), Southern of apical third; 3rd interval raised similarly to 2nd; 4th Pine Hills (II), Jackson Prairie (III), North-Central interval unevenly raised on basal half with highest Hills (VI), Flatwoods (VII), Pontotoc Ridge portion of elevation becoming strongly costate (VIII), Black Prairie (IX), Tombigbee-Tennessee just before middle, interval then becoming briefly River Hills (X), and Paleozoic Bottoms (XI) interrupted from mid-length, strongly callused on physiographic regions (Fig. 7). the beginning of apical third; 6th and 8th intervals Material Examined — We have examined 63 are distinctly convex, with the 6th interval becoming specimens from Mississippi localities, including: very briefly costate just anterior to callus on th4 George Co. 12 mi SW Lucedale, Pascagoula interval; 8th interval becoming briefly costate near WMA [UMIC]; 7 mi S Benndale [MEM]; Mixon mid-length; epipleuron irregularly punctate. Lakes, 30°50’28”N, 88°45’11”W [MEM]; 3.2 mi Male genitalia. Figure 6. Phallobase subequal S, 1.8 mi E Benndale [MEM], Jackson Co. MS in length to parameres; apex round; width equal Sandhill Crane NWR, 30°27’34”N, 88°41’28”W throughout, except tapering basally and at junction [MEM]; 11 mi NW Van Cleave [UMIC], Lafayette with parameres, equal to parameres in maximum Co. 4 mi E Abbeville [UMIC], Lamar Co. 5 mi N width; basoventral opening terminal, cordate. Baxterville [UMIC], Lauderdale Co. 3 mi S Arundel Apicoventral space triangular, widest at junction [UMIC], Madison Co. 7.5 mi SE Canton [UMIC], of parameres and phallobase and narrowing to Neshoba Co. 1.5 mi N Dixon [UMIC], Noxubee Co. acuminate angulation. Parameres symmetrical, Noxubee NWR, 33°16’08”N, 88°47’47”W [MEM]; widest at base, tapering to apex, widening in apical Noxubee NWR, 33°15’31”N, 88°46’03”W [MEM]; fifth before narrowing to apex; in lateral view, Noxubee NWR, 33°14’04”N, 88°48’31”W [MEM]; tapering toward apex, ventral surface concave in Noxubee NWR, 33°15’22”N, 88°47’46”W [MEM]; apical half, appearing weakly decurved; apices of Noxubee NWR, 33°16’19”N, 88°45’43”W [MEM]; parameres slightly deflexed. Aedeagus four-fifths Noxubee NWR, 33°16’24”N, 88°46’04”W [MEM]; length of parameres; in lateral view, tapering to Noxubee NWR, 33°16’23”N, 88°46’03”W [MEM], apex, with apex terminating below ventral margin Oktibbeha Co. 7 mi S Starkville, 33°20’04”N, of parameres, acuminate, apical half of ventral 88°49’06”W [MEM]; 3 mi W of Adaton, surface concave; in lateral view, possessing three 33°29’00”N, 88°58’13”W [MEM], Pontotoc Co. 1 dorsal swellings, the swellings decreasing in size mi SE Ecru [MEM], Simpson Co. 2 mi W Pinola towards apex, sinuate dorsally; in dorsal view, [UMIC]; Tanyard Creek x Hwy 28 [UMIC], Stone forked in apical third, rounded and widest basally, Co. Red Creek x Hwy 15 [UMIC]; UM Forestlands apices parallel and fine. Aedeagus with single, [UMIC], Tishomingo Co. Tishomingo State posterior, median process extending one-half length Park [UMIC], and Winston Co. Tombigbee NF, of apicoventral space of phallobase. 33°11’50”N, 89°03’20”W [MEM]; Noxubee NWR, Female — Indistinguishable from males. 33°13’44”N, 88°54’34”W [MEM]. Variation — The specimens examined varied Seasonal Distribution — Early April through in length from 2.7–3.5 mm and width from 1.2–1.4 late September. mm. The elytral intervals show considerable Diagnosis — Hydrochus inaequalis most variation in the degree of elevation and width. Some closely resembles H. excavatus and H. pajnii. specimens have very narrow intervals with the serial Hydrochus inaequalis, in general, is slightly smaller punctures nearly touching across the interval. and has less elevated and narrower calli on the 4th Distribution — The known distribution of H. elytral interval than seen in H. pajnii. Hydrochus inaequalis is rather disjunct. The species occurs inaequalis bears irregular epipleural punctation, from New Jersey south to Florida and as far unlike the punctation in H. excavatus, which is 178 hydrochidae of Mississippi

arranged in a single series. Due to variability and apically sagittate parameres, and, in lateral view, the character overlap between species in size and dorsal surface of aedeagus is flattened.Hydrochus prominence of elytral calli on the 4th interval, inaequalis lacks pseudoparameres, possesses this character is often unreliable for species acuminate, parallel parameres and, in lateral view, discrimination; however, structure of the male the dorsal surface of the aedeagus is sinuate with genitalia will distinguish the species immediately three swellings. (see diagnosis of H. excavatus). Biology — Hydrochus inaequalis has been Hydrochus neosquamifer Smetana, 1988 collected near ponds, ditches, and small pools using ultraviolet light (Ciegler 2003). Mississippi Hydrochus neosquamifer Smetana 1988: 14. specimens were collected near ponds in coastal Hydrochus neosquamifer Hellman 1975: 109 in White et savannah, mixed mesic forest, mixed forest, pine al. 1985. Nomen nudum. forest, and bottomland hardwood forest, near swamps, and in a field of cultivated cotton, as well Description — Male--Small, dark, elongate; as various streams and rivers, using black lights, maximum length 2.5 mm, maximum width 1.0 mercury vapor lights, and sun lamps. mm; maximum width of head across eyes 0.7 mm, Notes — Hydrochus inaequalis LeConte was minimum interocular distance 0.4 mm; maximum considered by Young (1954) as a synonym of H. length of pronotum 0.6 mm, maximum width 0.7 foveatus Haldeman, a status accepted by Hansen mm, minimum width near base 0.6 mm; maximum (1999). Examination of external characteristics length of elytra 1.7 mm. formed the basis for Young’s synonymy. Dorsum shiny, ground color of head and Examination of the holotype of H. inaequalis, pronotum piceous with the granulate elevated a male, and a lectotype female of H. foveatus areas marked with bright metallic green spots, indicated that these are two distinct species. Young spots occasionally coalesced, forming irregular (1954) believed these two species to be sympatric metallic areas on disc; elytron rufopiceous with in Florida based on information presented by Leng anterior and lateral margins and elevated areas on and Mutchler (1918) concerning manuscript notes intervals conspicuously marked with metallic green of Schwarz. However, H. foveatus is recorded only coalesced spots in short stripes, remaining areas on from Texas and Mexico, while H. inaequalis has intervals bear small to nearly imperceptible metallic only been recorded as far west as Louisiana, and the spots arranged in linear series of varying lengths. two are not known to have overlapping ranges. Antennae and palpi reddish brown, with apex of The following characters serve to differentiate ultimate maxillary palpomere darkened. Mentum H. inaequalis from H. foveatus. Externally, H. and submentum piceous. Legs reddish brown with foveatus bears impunctate to sparsely punctate the tibiofemoral joints and apex of tarsi piceous or raised areas surrounding deep pronotal foveae. dark brown. Hydrochus inaequalis possess evenly punctate Head across eyes equal to width of pronotum; raised areas encompassing shallow pronotal foveae. clypeus rugose with granulate-punctation, punctures The epipleuron of H. inaequalis is irregularly moderately dense, moderately coarse, occasionally punctate, while H. foveatus is impunctate, but bears coalesced; fine setae present, but frequently minute granules on the distal lateral margin in the obscured by metallic green spot reflections; apical half, but sometimes these are evident basally. epistomal sulcus fine near lateral margins, then Anterior margin of pronotum medially arcuate in H. gradually broadened and deeply impressed toward foveatus, but straight in H. inaequalis. Hydrochus middle, sulcus nearly obscured medially by inaequalis is typically smaller (length 2.7 to 3.5 coalesced punctation; interocular region much more mm), while H. foveatus is generally larger (3.3. to rugose and granulate than clypeus; mid-cranial and 3.9 mm). The characteristics of the male genitalia submedial depressions shallow but conspicuous, are dramatically different between the two species. with coalesced punctures; elevated areas adjacent to Hydrochus foveatus possesses pseudoparameres, depressions slightly less punctate than surrounding worthington et al. 179

discal surface; setae same as on clypeus; mid- broadened to mid-length, then interrupted and flat occipital region slightly constricted between to beginning of apical third where slightly callused, posterolateral margin of eyes. Mentum very finely, callus weakly elevated, elongate, slightly wider densely punctate, basal two-thirds of disc deeply than anterior costa on interval; 6th and 8th intervals foveate; submentum impunctate with disc nearly more strongly convex than adjacent odd numbered completely obscured by two very large, transverse, intervals; 7th interval sinuate near middle and deep foveae. nearly coalesced with 8th interval; epipleuron feebly Pronotum moderately convex, imperceptibly concave and punctate from base to apical fourth, wider than long, widest just behind anterior punctures rather large, irregular, very shallow. angles; anterior margin straight; lateral margins Male genitalia. Figure 8. Phallobase subequal very strongly, narrowly inflexed; inflexed surface to parameres in length; apex round, open; widest rugose, and punctate, same as on dorsum; sides medially, tapering to base and junction with of pronotum viewed above shallowly crenate, parameres, always more narrow than parameres; angulate, sinuate with apical half arcuate, then basoventral opening terminal. Apicoventral recurved behind middle and narrowed to base; space large, widest at junction of parameres and posterior margin arcuate; discal sculpture coarsely phallobase, sides straight before curving and granulate punctate, granules flat on top, those near narrowing to posterior, acuminate angulation. midline low to indistinct but gradually increasing in Parameres symmetrical, tapering to apex; in height toward lateral margin, punctures moderately lateral view, tapering toward apex, ventral surface coarse, irregularly spaced with most separated by moderately flat to apex, dorsal surface rounded one-half to one-third their width. Anterolateral and approximately equal in elevation in basal two- and basolateral foveae small, moderately deep, thirds then tapering to apex; apices straight, inner open to anterior pronotal margin; mediolateral and margin straight, outer margins weakly sinuate. basomedial foveae moderately deep, round and Aedeagus extending six-sevenths of parameres; in similar in outline; basomedial pair slightly more lateral view, ventral surface flattened, apex blunted, irregular and slightly smaller than others. dorsum elevated above dorsal surface of paramere Elytron convex, elongate, subparallel; lateral at junction with phallobase, flattened in apical half, margin feebly explanate medially, moderately gradually tapering to apex, apical fifth extending arcuate medially to apex; apex rounded; serial above dorsal surface of parameres; in dorsal punctures coarse, deep, those on disc separated view, forked in apical half, tines parallel and thin; by less than one-half their width, those in apical posterior projection of aedeagus extending three- fourth becoming smaller and denser; setae same fourths length of apicoventral space of phallobase, as on pronotum but obscured by shiny reflections; forked in apical half of extension. sutural interval wide and subcostate near base, then Females — Indistinguishable from males. gradually becoming slightly wider posteriorly and Variation — Specimens vary in length from costate on apical third; remaining intervals very 2.3–3.0 mm and in width from 0.8–1.3 mm. narrow, most separated on disc by slightly more The density of metallic spots on the head and than twice their width, even numbered intervals pronotal elevated areas varies considerably from slightly more convex and unequally costate; nearly no spots to the spots appearing coalesced. intervals unequally raised and widened as follows: Some specimens have little to no green metallic 2nd interval slightly raised and broadened on basal reflections. These specimens are dark, but retain fourth, then interrupted to mid-length where again a shiny appearance. Specimens from the southern becoming slightly raised and broadened to the end of the range lack the spots typical of northern beginning of apical third; 3rd interval raised like 2nd forms of this species. Pronotal foveae may be more interval on the basal eighth, then again raised like shallow, but are rarely deeper than described above. 2nd just behind mid-length to beginning of apical Distribution — Hydrochus neosquamifer third; 4th interval unevenly raised behind base to occurs from Virginia to Maine, into Canada basal third where becoming slightly costate and (Ontario and Quebec), as far west as Wisconsin and 180 hydrochidae of Mississippi

North Dakota and south from Indiana through the Description — Male--Elongate, slightly Mississippi River Basin to Mississippi. (Hilsenhoff broadened; maximum length 3.4 mm, maximum 1995a, 1995b, Smetana 1988, White et al. 1985). width 1.3 mm; width of head across eyes 0.8 mm, This species is known from disjunct localities in the minimum interocular distance 0.8 mm; maximum Loess Hills (IV), Alluvial Plain (V), North-Central length of pronotum 0.8 mm, maximum width 0.8 Hills (VI), Flatwoods (VII), Pontotoc Ridge (VIII), mm, minimum width near base 0.75 mm; maximum Black Prairie (IX), and Tombigbee and Tennessee length of elytra 2.3 mm. River Hills (X) physiographic regions in Mississippi Dorsum shiny, head piceous, pronotum and (Fig. 9). elytra brown, often with metallic green reflections Material Examined — We have examined eight obscuring nearly all ground color. Mentum specimens from Mississippi localities, including: and submentum same color as dorsum of head. Noxubee Co. Noxubee NWR, 33°16’34”N, Antennae and palpi reddish brown with base and 88°44’33”W [MEM]; Noxubee NWR, 33°16’19”N, apex of each tarsomere darkened. Legs reddish 88°45’43”W [MEM], Tallahatchie Co., and Winston brown with tibiofemoral joints and apex of tarsi Noxubee NWR, 33°13’53”N, 88°54’32”W [MEM]. darkened. Seasonal Distribution — Late July to late Head across eyes as wide as pronotum; clypeal August. punctures moderately coarse, dense, irregularly Diagnosis — Hydrochus neosquamifer most spaced; coarser punctures with numerous fine setae closely resembles H. rufipes; however, the former interspersed, but setae often obscured by shiny is generally smaller and the elytral calli are less reflections; epistomal sulcus fine near margins, prominent on 4th elytral interval than they are gradually broadened and deeply impressed toward in H. rufipes. Examination of the male genitalia middle, coarse punctures within sulcus coalesced; will provide positive identification, particularly interocular region rugose, gradually, irregularly following careful comparison of the shape of the raised to vertex behind epistomal sulcus; mid- apicoventral space of the phallobase. In H. rufipes, cranial depression short, deeply sulcate and this space is smaller and sagittate or triangular, coarsely punctate, punctures coalesced; submedial while in H. neosquamifer the space is larger with interocular depression deep, broader than mid- nearly parallel sides in basal half. cranial depression; elevated areas of disc more Biology — All Mississippi specimens were sparsely punctate than surrounding discal surface; collected near water in bottomland hardwood or most punctures moderately large, very irregularly mixed forest using black light. Specimens from and closely spaced, randomly coalesced; mentum previous studies were collected around ponds and finely, densely punctate, basal two-thirds of disc marshes (Hilsenhoff 1995a). moderately, deeply foveate medially; submentum Notes — The name Hydrochus neosquamifer sparsely, finely punctate with disc bearing two large, was first ascribed to Hellman in the checklist deep foveae. presented by White et. al. 1985, though no Pronotum moderately convex, as wide as description had been published. Smetana (1988) long, widest in apical half; anterior margin straight first formally described the species using the same medially with anterolateral angles indistinctly specific epithet. produced; lateral margins strongly, moderately broadly inflexed; inflexed portion punctate, similar Hydrochus rufipes Melsheimer, 1844 to that on dorsum; sides of pronotum viewed from above rounded, feebly crenate, sinuate in outline Hydrochus rufipes Melsheimer 1844: 100. with apical half arcuate, then slightly incurved Hydrochous rufipes Melsheimer; Zaitzev, 1908a: 335. behind middle and moderately narrowed to base; Hydrochus impressus Zimmermann, 1869: 249; Syn.: posterior margin moderately arcuate medially; Smetana, 1988: 18. punctures moderately coarse, slightly larger than Hydrochous impressus Zimmermann; Zaitzev, 1908a: on head, very irregularly, closely spaced, those 335. near lateral and anterior margins denser and finer; worthington et al. 181 elevated areas laterally adjacent to median fovea lateral view, dorsal surface flattened, ventral surface with only a small impunctate area, remaining area flat in basal half, tapering to apex in apical half, punctate; setae same as on head. Anterolateral and apex truncate; dorsally extended above dorsal basolateral foveae similar, small, moderately deep; surface of paramere in apical seventh; in dorsal median and mediolateral foveae shallow, rounded, view, forked in apical third, tines fine, parallel, with median fovea slightly less than one-fourth converging at apex. Aedeagus with posterior, length of pronotum; basomedial foveae slightly narrowed process extending two-thirds length of smaller and more irregular than median fovea. apicoventral space of phallobase, extension of Elytron moderately strongly convex, elongate; aedeagus widening at apex producing small, apical lateral margin feebly constricted in basal third, concavity. slightly explanate medially then moderately arcuate Female — Indistinguishable from males. to apex; apex rounded to suture; serial punctures Variation — Length of specimens examined coarse, deep, those on disc separated by nearly varies from 2.7–3.8 mm and width from 1.2–1.4 one-third width of a puncture, those on apical third mm. The intensity of the metallic reflections varies smaller and denser; fine setae on intervals obscured from bright and shiny to the opposite extreme where by metallic reflections; sutural interval flat, wider specimens appear dull and dark. Frequently the than other intervals at base, then posteriorly brown ground colors will show through the metallic becoming gradually wider and costate on apical green reflections. Specimens often have two small, third; remaining intervals on elytron narrower irregular maculae on each elytron, one just before than serial rows of punctures, most separated by middle on the 2nd interval and a second more approximately twice width of an interval, intervals variable macula just anterior to the callus on the 4th are unequally raised as follows: intervals 1-3 interval. As with most hydrochid species, there is slightly raised on basal sixth, 2nd and 3rd intervals some variation in the density of punctation, as well similarly moderately costate from mid-length to as width and height of the elytral intervals. beginning of apical third, 3rd slightly costate just Distribution — The range of Hydrochus rufipes before mid-length, then interrupted, flat medially extends from Florida north to Michigan and west to and then slightly callused on beginning of apical Wyoming and Texas, making this one of the most third; 6th and 8th unequally convex and raised above widely distributed species of Hydrochus in North adjacent odd numbered intervals; 7th interval near America (Arnett 1983; Hilsenhoff 1995a, 1995b; middle slightly sinuate and nearly coalesced with Hubbard et al. 1878; Smetana 1988; White et al. 8th interval; epipleuron feebly concave and very 1985). Hydrochus rufipes is widely distributed in shallowly, finely punctate on basal three-fourths. Mississippi, occurring throughout the state with the Male genitalia. Figure 10. Phallobase equal to exception of the coastal counties (Fig. 11). length of parameres; apex pointed; widest medially, Material Examined — We have examined 447 tapering to base and junction with parameres, specimens from Mississippi localities, including: maximum width same as parameres; basoventral Adams Co. Natchez State Park [UMIC]; 14 mi opening terminal, cordate. Apicoventral space E Sibley, Pipe Lake [UMIC]; Natchez [UMIC], triangular or sagittate in form, widest immediately Alcorn Co. 15.5 mi W Corinth [UMIC], Bolivar Co. behind junction of parameres and phallobase and 2 mi W Rosedale [UMIC]; Mississippi River Levee, narrowing to acuminate angulation. Parameres 33°36’29”N, 91°07’34”W [MEM], Calhoun Co. symmetrical, widest at base, tapering to apex, 13 mi NE Bruce [UMIC]; Calhoun City [UMIC]; 4 inner and outer margins sinuate; in lateral view, mi SW Calhoun City [UMIC]; T11S-R3W-Sec.25 tapering toward apex, ventral surface mostly flat, [UMIC], Carroll Co. Carrollton [UMIC], Choctaw but upturned in apical fifth, dorsal surface narrowed Co. 12.5 mi NNE Weir [UMIC], Claiborne Co. at junction with phallobase and extending to basal Kennison Creek, 1.5 mi N Willows [UMIC]; fourth of paramere, convex and highest medially, Little Sandy Creek at Rocky Springs [UMIC]; apical one-fourth tapering and reflexed to apex. Natchez Trace Parkway, mile 41.6 [MEM], Clarke Aedeagus six-sevenths length of parameres; in Co. 1.5 mi N Enterprise [UMIC], Clay Co. 5 mi 182 hydrochidae of Mississippi

W West Point [UMIC], Copiah Co., Forrest Co. 88°52’56”W [MEM], Perry Co. Redhill Branch P.B. Johnson State Park [MEM], Franklin Co. @Rte 304, Desoto NF [UMIC], Pontotoc Co. Richardson Creek, Homochitto NF [UMIC]; Tally’s Toccopola Creek @ Hwy 334 [UMIC]; Mud Creek, Homochitto NF [UMIC]; George Co. 12 mi Creek at Hwy 6 [UMIC]; 1 mi SE Ecru [MEM]; SW Lucedale [UMIC]; 4.5 mi NNW Lucedale, T1S, Two Mile Creek @ Hwy 334 [UMIC], Scott Co. R6W, Sec. 6E [MEM]; Pascagoula River WMA, Pinkston Hill, 32°16’06”N, 89°23’33”W [MEM]; 30°52’40”N, 88°46’05”W [MEM]; Black Creek x Golden Memorial State Park [UMIC], Smith Co. Hwy 57 [MEM]; 7 mi S Benndale [MEM]; Mixon 3 mi W Lake Marathon [UMIC]; Mize [UMIC], Lakes, 30°50’28”N, 88°45’11”W [MEM]; 3.2 mi Stone Co. Red Creek x Hwy 15 [UMIC]; UM S, 1.8 mi E Benndale [MEM], Humphreys Co. 10 Forestlands [UMIC]; 10.5 mi ESE Perkinston mi SW Belzoni [UMIC], Issaquena Co. 0.7 mi S [UMIC], Sunflower Co. 5 mi SE Indianola [UMIC], Valley Park [UMIC]; Anderson-Tully WMA, 6.5 Tallahatchie Co. Tallahatchie River, 4.5 mi WNW mi SSW Mayersville [UMIC], Jasper Co. 6 mi NW Charleston [UMIC]; 3 mi S Charleston [UMIC]; Montrose [UMIC], Kemper Co. Pawticfow Creek 8 mi ESE Charleston [UMIC], Tippah Co. 4 mi N x Hwy 39 [UMIC]; 2 mi N Scooba, T12N, R18E, Ripley [UMIC], Tishomingo Co. Tishomingo State Sec. 29, 30 [MEM], Lafayette Co. 5 mi E Oxford Park [UMIC]; 5 mi E Tishomingo [UMIC]; 1.5 [UMIC]; Puskus Lake [UMIC]; Oxford [UMIC]; 7 mi NW Belmont [UMIC]; Tombigbee Waterway, mi NW Oxford [UMIC]; T8S-R4W Sec. 5 [UMIC]; 34°30’18”N, 88°19’13”W [MEM], Tunica Co. 6 mi ENE Oxford [UMIC]; T7S-R2W Sec. 34 5.5 mi W Robinsonville [UMIC], Union Co. 11 [UMIC]; T7S-R2W Sec. 25 [UMIC]; 7 mi WNW mi W New Albany [UMIC], Washington Co. Oxford [UMIC]; 5 mi N Oxford [UMIC]; 5 mi NW Leroy Percy State Park, 33°10’17”N, 90°56’10”W Oxford [UMIC]; T7S-R4W Sec. 24 [UMIC]; 9 mi [MEM], Winston Co. Tombigbee NF, 33°16’05”N, NE Oxford [UMIC]; 8 mi NE Oxford, UM Field 89°06’01”W [MEM]; Tombigbee NF, 33°13’01”N, Station [UMIC]; 9 mi E Oxford [UMIC], Lamar Co. 89°05’42”W [MEM]; Noxubee NWR, 33°13’44”N, 5 mi N Baxterville [UMIC, MEM], Lauderdale Co. 88°54’34”W [MEM]; Noxubee NWR, 33°14’29”N, 3 mi S Arundel [UMIC]; 1.5 mi SSE Collinsville 88°49’03”W [MEM]; Tombigbee NF, 33°11’50”N, [UMIC], Lowndes Co. T17N, R16E, Sec. 5 [MEM]; 89°03’20”W [MEM]; Tombigbee NF, 33°12’53”N, Lake Lowndes State Park [MEM]; Black Belt 89°06’10”W [MEM]; Noxubee NWR, T16N, R14E, Prairie, 33°18’01”N, 88°36’38”W [MEM]; Hwy Sec. 13SE [MEM], and Yalobusha Co. Tillatoba 82 X 45 Alt., 33°29’17”N, 88°39’38”W [MEM]; Lake [UMIC]. Black Belt Prairie, T17N, R16E, Sec. 34 [MEM]; 2 Seasonal Distribution — Late February mi E Artesia [UMIC], Madison Co. Lake Barnett, through mid-November. NE of Jackson [MEM]; 7.5 mi SE Canton [UMIC], Diagnosis — Hydrochus rufipes externally Marshall Co. Wall Doxey State Park [UMIC], most closely resembles H. pajnii. Generally, H. Neshoba Co. 1.5 mi N Dixon [UMIC]; 7 mi SW pajnii has narrower, but more prominent calli on the Philadelphia [UMIC], Noxubee Co. 4 mi N Macon 4th elytral interval than does H. rufipes. Examination [UMIC]; 10 mi W Macon [UMIC]; Noxubee of male genitalia, however, is required for positive NWR [MEM]; Noxubee NWR, 33°16’34”N, identification. Configuration of the genitalia is 88°44’33”W [MEM]; Noxubee NWR, 33°16’19”N, most similar to those of H. neosquamifer and 88°45’43”W [MEM]; Noxubee NWR, 33°15’22”N, careful comparison of the shape and size of the 88°47’46”W [MEM]; Noxubee NWR, 33°15’31”N, apicoventral space of the phallobase is necessary 88°46’03”W [MEM], Oktibbeha Co. Adaton to differentiate between these species. Externally, [MEM]; Craig Spring [MEM]; Starkville [MEM]; H. neosquamifer is smaller and has reduced elytral 3 mi W of Adaton, 33°29’00”N, 88°58’13”W calli in comparison to H. rufipes. [MEM]; 6 mi SW Starkville [MEM]; T19N, R15E, Biology — Hydrochus rufipes inhabits a Sec. 16 [MEM]; Dorman Lake [MEM]; Sessums, wide variety of aquatic habitats including rivers, 33°23’31”N, 88°42’40”W [MEM]; Osborn streams, ponds, backwaters, sloughs, and ditches Prairie [MEM]; Noxubee NWR, 33°21’23”N, and are frequently collected using ultraviolet light worthington et al. 183

(Ciegler 2003; Hilsenhoff 1995a; Smetana 1988). obscuring nearly all ground color. Mentum and Mississippi specimens were collected in small submentum with same metallic reflections as streams, ponds, swamps, a field of cultivated cotton, dorsal surface. Antennae and palpi reddish brown, oak-hickory forest, deciduous forest, bottomland with apical half of ultimate maxillary palpomere hardwood forest, Jackson prairie remnants, Sweet distinctly dark brown or piceous. Legs dark brown, Bay (Magnolia virginiana L.) bog in mixed mesic with tibia and tarsi much paler, testaceous; the forest, and mixed forest using white pan traps, flight tibiofemoral joints, apex of tibiae, and apex of tarsi intercept traps, mercury vapor lights, sun lamps, and piceous. Epipleura with same metallic reflections as black lights. dorsum of elytra. Notes — Ciegler (2003) attributed the Head across eyes imperceptibly narrower synonymy of Hydrochus impressus Zimmermann than width of pronotum; clypeal punctures very 1869: 249 with H. rufipes to Brigham (1982: dense, moderately coarse, those on base finer than 10.96). However, Brigham (1982) clearly indicated those on interocular region; coarser punctures that the exclusion of H. impressus from the key interspersed with numerous, nearly imperceptible was due to the lack of available specimens for fine setae, most very short and obscured by metallic examination and actually gave no indication of this reflections; epistomal sulcus fine near lateral specific synonymy in the text. The synonymy of margins; gradually broadened and coarsely punctate H. impressus Zimmermann should be attributed to toward middle, punctures on middle two-thirds Smetana (1988: 18). Hellman (1975) was unable deep, coalesced; interocular region rugose, medially to locate the type of H. rufipes, however a single very gradually and unevenly raised to vertex behind specimen of that species believed to have come epistomal sulcus; mid-cranial depression very from the Melsheimer collection was obtained from deeply sulcate, and coarsely punctate, individual the MCZ, but proved to be a male of H. subcupreus punctures coalesced so that sides of sulcus appear Randall. The type of H. rufipes is deemed lost or nearly straight; submedial interocular depressions destroyed, and so we here designate a neotype irregular, moderately deep and wide, with closer in its place. The neotype male with label data, punctures than on the surrounding punctate elevated stated verbatim, with line breaks indicated by areas on disc; most punctures moderately large, “/”: “Sunflower Co. MS/5 mi. SE Indianola/Sam irregularly spaced, several near eyes coalesced; Testa”, is deposited in the Museum of Comparative setae same as on clypeus; mid-occipital region Zoology, Harvard University. broadly, moderately and shallowly constricted between posterolateral margin of eyes. Mentum Hydrochus rugosus Mulsant, 1844 finely, very densely punctate, disc deeply foveate medially on basal half; submentum very sparsely Hydrochus rugosus Mulsant 1844c: 373. and finely punctate, with disc nearly completely Hydrochous rugosus Mulsant; Zaitzev 1908a: 335. covered by two large, moderately deep foveae. Hydrochus grandis Motschulsky 1860: 104. Pronotum moderately convex, slightly wider Hydrochus hanoewanti Makhan 1994: 42. New than long, widest in apical half; anterior margin Synonym arcuate in middle, and feebly incurved behind eyes so that anterior angles are very slightly produced Description — Male—Elongate, subparallel; anteriorly; lateral margins very sharply, broadly maximum length 6.0 mm, maximum width of head inflexed; sculpture on inflexed sides very smooth, across eyes 1.3 mm, minimum interocular distance impunctate; sides of pronotum viewed from above 0.8 mm, maximum length of pronotum 1.3 mm, rounded, crenate teeth exceedingly fine, close maximum width 1.4 mm, minimum width near base with shallow interspaces, sides sinuate in outline 1.3 mm, maximum length of elytra 4.1 mm. with apical half subparallel then very shallowly Dorsum somewhat dull, head piceous; incurved behind middle and moderately narrowed pronotum and elytra brown, but with bright green to to base; posterior margin strongly arcuate medially; gray-green and scattered violet metallic reflections punctures moderately coarse, not much larger 184 hydrochidae of Mississippi

than those on interocular region, punctures deep, to apex; in lateral view, ventral surface flat, dorsal irregularly spaced, those on disc separated by one- surface equal in elevation to dorsum of phallobase, half to nearly width of a puncture, denser and finer paramere beyond junction with phallobase raised toward anterolateral margins; elevated areas of and rounded one-half length of parameres, apical disc punctate. Anterolateral and basolateral foveae half of parameres tapering gradually to apex, apex small, very deep with three or four coalesced blunted, straight. Aedeagus seven-eighths length punctures in middle; median fovea and mediolateral of parameres; in lateral view, ventral surface flat, foveae shallow rather similar in size and form, dorsal surface with three swellings decreasing in median fovea slightly deeper than lateral foveae; size towards apex, two apical swellings extending basomedial foveae same depth as median fovea, above dorsal surface of parameres, apex weakly elongate and convergent near base. acuminate; in dorsal view, forked in apical fifth; Elytron strongly convex, elongate; lateral aedeagus with posterior process extending two- margin moderately constricted on basal third, thirds length of apicoventral space of phallobase as narrowly explanate medially, then moderately a forked process, apices rounded. arcuate to apex; apex abruptly rounded to suture; Female — Indistinguishable from males. serial punctures very coarse, very deep, those on Variation — Specimens vary in length from disc separated by less than one-half width of a 4.8–6.1 mm and in width from 1.7–2.2 mm. Some puncture, those on apical third smaller and denser; specimens exhibit very dark to piceous color sutural interval near base flat, wider, and only forms, while others show coarser and denser dorsal slightly raised above others, posteriorly becoming punctuation than is mentioned above. Additionally, very gradually wider and costate on apical third; some individuals exhibit wider elytral intervals with remaining intervals narrow separated on disc by much finer serial punctures than described. slightly more than their width, most appear flat Distribution — Hydrochus rugosus is found and regular except as follows: 2nd interval slightly from Massachusetts to Florida and as far west raised from midlength to beginning of apical third; as Texas (Ciegler 2003; Young 1954), and has 3rd interval appears moderately costate and elevated been reported from Cuba (Blackwelder 1944). together with 2nd interval and part of 4th interval The species occurs as far north in the Mississippi to form a broad low elongate keel from behind River Valley as Arkansas (Hellman 1975), who middle to just anterior to callus on apical third also stated that a single specimen from Indiana of 4th interval; 4th interval moderately callose on had been identified as this species, but questioned beginning of apical third, callus moderately high, the validity of the locality and remained skeptical short, moderately broad, primarily restricted to of the potential northern range extension of the the 4th interval; 6th interval more strongly convex species until further material could be examined. than adjacent odd numbered intervals; 7th interval Young (1954) noted that H. rugosus was commonly near middle strongly sinuate and nearly coalesced encountered in the peninsular uplands of Florida. with 8th interval; 8th interval irregularly subcostate This species is widely distributed throughout except medially where slightly raised and widened; Mississippi, with the exception of the coastal epipleuron smooth and impunctate. counties (Fig. 13). Male genitalia. Figure 12. Phallobase Material Examined — We have examined 128 approximately equal to length of parameres; specimens from Mississippi localities, including: apex round; widest medially, tapering to base Adams Co. 14 mi E Sibley, Pipe Lake [UMIC], and junction with parameres, maximum width Amite Co. Homochitto NF, 3.5 mi E Rosetta, Mt. equal to parameres; basoventral opening terminal. Nebo Camp [UMIC], Choctaw Co. Ackerman Apicoventral space of phallobase deltoid to weakly [UMIC], Desoto Co. Southaven [UMIC], Forrest sagittate, widest at junction of parameres and Co. 1 mi N Fruitland Park [UMIC], George Co. 12 phallobase and narrowing to acuminate angulation. mi SW Lucedale [UMIC, MEM]; 7 mi S Benndale Parameres symmetrical, widest at base, tapering to [MEM]; Pascagoula River WMA, 30°52’40”N, apex, dorsal view, outer margin straight, curving 88°46’05”W [MEM], Greene Co. Stateline [MEM], worthington et al. 185

Grenada Co. T22N, R3E, Sec. 31NW [MEM], intercept traps and at mercury vapor lights. Hancock Co. Stennis Space Center [UMIC], Notes — Although he had not seen the Harrison Co. 8 mi NE Saucier [UMIC]; 12.5 mi holotype, Epler (1996) suggested that Hydrochus E Saucier [UMIC], Jackson Co. 4 mi SW Hurley hanoewanti Makhan (1994), described from a [UMIC]; MS Sandhill Crane NWR, 30°27’34”N, single specimen collected near Jacksonville, FL, 88°41’28”W [MEM]; Grand Bay Savannah, was a junior synonym of H. rugosus. Following 30°27’31”N, 88°25’14”W [MEM]; 11 mi NW examination of the holotype bearing the label data, Van Cleave [UMIC], Kemper Co. 2 mi N Scooba, stated verbatim, with line breaks indicated by “/”: T12N, R18E, Sec. 29,20 [MEM], Lafayette Co. “St. John’s Bluff/East Florida/R. Foster/Hist.-Coll./ T7S-R2W-Sec. 34 [UMIC]; Oxford [UMIC]; 5 Nr. 10744”, deposited in the Berlin Natural History mi E Oxford [UMIC]; 8 mi NE Oxford, UM Field Museum collection, we agree that H. hanoewanti Station [UMIC], Lamar Co. 5 mi N Baxterville Makhan, 1994 is a typical form of H. rugosus [UMIC, MEM], Leake Co. Carthage [UMIC], Mulsant, thus confirming Epler’s conclusion. Lowndes Co. T17N, R16E, Sec. 5 [MEM], Madison Hellman (1975) was unable to locate the type of H. Co. 7.5 mi SE Canton [UMIC], Marshall Co. Wall rugosus, which is deemed lost or destroyed, and so Doxey State Park [UMIC], Neshoba Co. 7 mi SW we designate a neotype in its place. The neotype Philadelphia [UMIC], Newton Co. 4 mi E Newton male, bearing the verbatim label, with line breaks [UMIC], Oktibbeha Co. Sessums, 33°23’31”N, indicated by “/”: “FLORIDA, 17mi.N./Tallahassee, 88°2’40”W [MEM]; 5 mi S of Starkville, Tall/ Timbers Res. Sta./12-22 July, 1967/ L. 33°22’47”N, 88°49’44”W [MEM]; 3 mi W of Collins”, is deposited in the National Museum of Adaton, 33°29’00”N, 88°58’13”W [MEM]; T18N, Natural History, Smithsonian Institution. R14E, Sec. 33SE [MEM]; Craig Spring [MEM], Pearl River Co. 1 mi SW Silver Run [UMIC], Pike Hydrochus simplex LeConte, 1855 Co. Percy Quinn State Park [UMIC], Scott Co. Golden Memorial State Park [UMIC], Stone Co. Hydrochus simplex LeConte 1855: 361. U.M. Forest Lands [UMIC]; 11 mi E Perkinston, Hydrochous simplex LeConte; Zaitzev, 1908a: 335. Red Creek [MEM]; Red Creek x Hwy 15 [UMIC], Hydrochus equicarinatus Blatchley 1928: 62. New Tishomingo Co. Tishomingo State Park [UMIC], Synonym Walthall Co. 6 mi NE Tylertown [UMIC], Wayne Co. 3.5 mi NW State Line [UMIC], Winston Co. Description — Male--Small, elongate, Noxubee NWR, T16N, R14E, Sec. 13SE [MEM], subparallel; maximum length 2.7 mm, maximum and Yazoo Co. 1 mi W Bentonia [UMIC]. width 1.0 mm, maximum width of head across eyes Seasonal Distribution — Early March through 0.7 mm, minimum interocular distance 0.3 mm; mid-November. maximum length of pronotum 0.6 mm, maximum Diagnosis — The large, elongate form width 0.7 mm, minimum width near base 0.6 mm; of H. rugosus and the unique male genitalia maximum length of elytra 1.8 mm. will differentiate this species from all others in Dorsum shiny, head piceous; pronotum and Mississippi. elytra dark reddish brown with bright metallic green Biology — This species is known to occur in and golden-green reflections obscuring nearly all sink hole ponds, along the margins of lakes, cypress ground color. Mentum and submentum piceous with swamps, and small streams found on or near aquatic reddish copper reflections on disc. Antennae and vegetation or floatage and has been collected using palpi reddish brown with apex of ultimate maxillary ultraviolet lights (Ciegler 2003; Young 1954). palpomere darkened. Legs reddish brown, tibia Mississippi specimens were collected in mixed slightly paler, base of femora darkened, tibiofemoral pine-oak forest, coastal savannah, near streams, joints and apex of ultimate tarsomeres piceous. rivers, marshes and swampy areas, as well as small Head across eyes as wide as pronotum; clypeal and large impoundments. Most were collected using punctures moderately coarse, dense, not much finer black light traps, but some were taken in flight than on interocular region; exceedingly fine setae 186 hydrochidae of Mississippi interspaced between coarser punctures frequently costate on apical third; remaining intervals on obscured by bright metallic reflections; epistomal elytron narrow, flat, separated on disc by nearly sulcus fine near lateral margin, gradually broadened twice their width, most appear very regular in height and deeply impressed on middle two-thirds; coarse without any distinct interruptions except on middle punctures within epistomal depression coalesced; of 8th interval where only feebly raised; epipleuron interocular region rugose, medially behind flat, moderately, coarsely punctate, punctures on epistomal sulcus very gradually irregularly raised basal half rather shallow and regular, then behind to vertex; midcranial depression deeply sulcate and middle becoming gradually finer and shallower coarsely punctate, punctures coalesced; submedial before becoming indistinct in apical fourth. interocular depressions very irregular, shallow Male genitalia. Figure 14. Phallobase two- with slightly closer punctures than on surrounding, thirds length of parameres; apex pointed; widest punctate elevated areas on disc; most punctures in anterior third, tapering to base and junction moderately large, very irregularly spaced with with parameres, wider than parameres at junction random groups of 2’s, 3’s and rarely 4’s nearly with phallobase; basoventral opening terminal. coalesced; setae same as on clypeus; midoccipital Apicoventral space of phallobase sagittate with region broadly, moderately constricted between rounded basal lobes, widest at junction of parameres posterolateral margins of eyes. Mentum finely, very and phallobase and narrowing to acuminate densely punctate, basal ½ of disc deeply foveate angulation. Parameres symmetrical, widest in basal medially; submentum very sparsely and very finely half, tapering to apex; in lateral view, tapering punctate, with disc nearly completely covered by toward apex, ventral surface weakly concave in two large deep transverse, elongate foveae. basal two-thirds, flat in apical third, dorsum lower Pronotum moderately convex, as wide as long, than dorsal surface of phallobase at junction with apical half widest, anterior margin nearly straight; parameres, highest dorsal elevation at middle before lateral margins coarsely crenate, teeth rounded and tapering to apex; apices straight. Parameres widely regular; in dorsal view, appearing sinuate, with separated by aedeagus. Aedeagus seven-eighths lateral margins parallel in apical half, then weakly length of parameres; in lateral view, base elevated inflexed in basal half; posterior margin moderately above dorsal surface of parameres, tapering to arcuate; punctures moderately coarse, irregularly apex, ventral surface flat extending below ventral spaced, most punctures separated by more or less surface of parameres, ventral portion of aedeagus one-half width of puncture, denser and finer toward visible in concavity of paramere; aedeagus forked lateral margins; sculpture on elevated areas of disc in apical two-fifths, tines fine, parallel, apices nearly without smooth and impunctate areas. Anterolateral contiguous; aedeagus wide with posterior process and basolateral foveae small, deep, irregularly extending three-fourths length of apicoventral rounded; median and mediolateral foveae space of phallobase, forked at apex with tines short, moderately shallow, round, with median fovea broadly rounded. equal to one-fourth length of pronotum at midline; Female — Indistinguishable from males. basomedial foveae elongate, much shallower than Variation — Specimens vary in length from median fovea, convergent near base. 2.5–3.0 mm and in width from 0.9–1.1 mm. Elytron convex, elongate; lateral margins Metallic reflections typically variable. Minor slightly constricted, straight in apical third, then differences in depth of pronotal foveae and slightly arcuate medially to apical third where punctation density are apparent among the series of perceptibly constricted subapically; apex abruptly specimens examined. rounded to suture; serial punctures very coarse, Distribution — Hydrochus simplex ranges deep, those on disc separated by approximately from North Carolina south to Florida and west to one-half width of a puncture, those in apical fourth Louisiana. Ciegler (2003) indicated the species gradually smaller and denser; sutural interval is known from Arizona, but the latter requires near base wider than other intervals, posteriorly confirmation. Young (1954) found H. simplex to becoming gradually, slightly wider and moderately be common throughout upland peninsular Florida worthington et al. 187

and occasionally present in flatwood areas of the this species as a junior synonym of H. simplex, a panhandle and peninsula. Hydrochus simplex position previously suggested by Epler (1996). occurs primarily in the southern third of Mississippi (Fig. 15), including the Coastal Meadows (I) and Hydrochus jaechi Makhan, 1995 Southern Pine Hills (II), physiographic regions, with a few northern localities in the North-Central Hydrochus jaechi Makhan 1995a: 18. Hills (VI), Flatwoods (VII), Pontotoc Ridge (VIII), and Black Prairie (IX) regions. Description — Holotype Male—Large, Material Examined — We have examined 64 elongate; length 4.06 mm, width 1.58 mm; width specimens from Mississippi localities, including: of head across eyes 0.89 mm, interocular distance Greene Co., Hancock Co. Pt. Clear Island [UMIC]; 0.53 mm; length of pronotum 0.85 mm, width 0.95 6 mi WNW Waveland [UMIC]; Stennis Space mm, minimum width near base 0.73 mm, maximum Center [UMIC]; 2 mi N Waveland, Bayou La Croix length of elytra 2.72 mm. [MEM], Harrison Co. W Ship Island [MEM], Dorsum shiny, bicolored; ground color of Jackson Co. Grand Bay Savannah, 30°27’31”N, head piceous with scattered metallic blue, violet, 88°25’14”W [MEM]; MS Sandhill Crane NWR, and green reflections; pronotum and elytra very 30°27’34”N, 88°41’28”W [MEM]; Ocean Springs light yellow brown with more metallic green and [UMIC], Jeff Davis Co. [MEM], Lamar Co. 3.5 mi bronze reflections than on head; sutural intervals WNW Purvis [UMIC]; 5 mi N Baxterville [UMIC], and elevated areas on elytral intervals slightly paler. Oktibbeha Co. 8 mi NE Starkville [MEM]; 3 mi Mentum and submentum rufopiceous with same W of Adaton, 33°29’00”N, 88°58’13”W [MEM]; metallic reflections as on dorsum of head. Antennae, Adaton [MEM]; Osborn Prairie [MEM], and Stone palpi and legs yellow brown with only the Co. U.M. Forestlands [UMIC]; 13 mi SE Wiggins tibiofemoral joints and apex of ultimate tarsomeres [UMIC]. slightly darkened. Seasonal Distribution — Mid-March through Head across eyes as wide as pronotum; mid-September. clypeal punctures dense, moderately coarse, same Diagnosis — Hydrochus simplex is most as on interocular region; epistomal sulcus fine readily confused with H. schereri when examining near margins, gradually broadened and slightly external characteristics. Both species have densely impressed toward middle; interocular region rugose, punctate head and pronotal surfaces in comparison and gradually, irregularly raised to vertex medially to other Hydrochus species in Mississippi. Both behind epistomal sulcus; midcranial depression species have reduced elytral calli, but in our deeply sulcate and coarsely punctate, punctures opinion external characters are inadequate for coalesced; submedial interocular depressions differentiation. The phallobase in H. simplex is irregular, shallow, rather broad with punctures two-thirds the length of the parameres, while the only slightly closer than on surrounding elevated phallobase in H. schereri is one and one-half times areas; punctures moderately large, very dense, most the length of the parameres. separated by less than one-half width of puncture, Biology — Blatchley (1928) noted that H. some irregularly spaced; setae indistinct; mid- simplex (as H. equicarinatus) was collected from occipital region broadly, moderately constricted stems and debris of water purslane, Didiplis between posterolateral margins of eye. Mentum diandra (Nutt. ex. DC.) Alph. Wood. Specimens finely, densely punctate, basal half of disc deeply were previously known to be collected from rivers, foveate medially; submentum nearly completely ponds, ditches, and at ultraviolet lights (Ciegler covered by two large, deep foveae. 2003). In Mississippi, specimens were collected in Pronotum moderately convex, imperceptibly artesian ponds, coastal savannahs, on beaches, at wider than long, apical half widest near middle; marsh edges, and by sweeping and black lighting. anterior margin straight medially, then nearly Notes — Examination of the holotype of imperceptibly recurved behind eyes so that Hydrochus equicarinatus Blatchley confirmed anterolateral angles are slightly produced anteriorly, 188 hydrochidae of Mississippi

angles even with midline; lateral margins of and only slightly raise behind basal third to just pronotum sharply, moderately broadly inflexed; before middle where interval appears costate and inflexed surface slightly concave near middle slightly widened to the beginning of the apical third, and moderately, coarsely punctate, punctures 3rd interval only feebly raised in basal fourth, then same as on dorsum but arranged in a single linear interrupted and flat to just before middle where series; sides of pronotum angulate in dorsal view, interval appears costate to beginning of the apical coarsely crenate, slightly sinuate in outline with third, costa similar to adjacent costa on 2nd interval; apical half parallel, then shallowly incurved behind 4th interval unevenly costate over basal half but middle and slightly narrowed to base; posterior elevated higher from basal fourth to midlength margin moderately arcuate medially; punctures where interval interrupted, and only slightly raised very dense, moderately coarse, rather uniform in to beginning of the apical third, where moderately size but irregularly spaced with most separated by callose, callus elongate and only moderately less than one-third width of a puncture, becoming developed but higher than any costa on elytron; slightly closer and finer toward anterolateral 6th interval uniformly subcostate on basal third, margins; elevated areas adjacent to median fovea interrupted and depressed just behind midlength slightly more closely punctate than within fovea. to beginning of the apical third where briefly but Anterolateral foveae small, moderately deep, strongly costate, costa similar and adjacent to those irregular in form, anteriorly open to anterior margin on 2nd and 3rd intervals but slightly shorter in length; of pronotum; median and mediolateral foveae 7th interval near middle sinuate and nearly coalesced somewhat similar in form with median fovea with 8th interval; 8th interval unevenly costate over slightly deeper, round and equal to one-fourth most of its length, and only near middle becoming length of pronotum at midline; basomedial foveae prominently raised and widened; epipleuron elongate, slightly more irregular and shallower than coarsely punctate and concave on basal half, then median fovea and convergent near base; basolateral between middle and apical fourth gradually less foveae similar to anterolateral pair but open concave and punctures becoming shallower and posteriorly to margin of pronotum. smaller until disappearing. Elytron strongly convex, elongate; lateral Male genitalia. Figure 17. Phallobase one margin slightly constricted, straight in basal third and one-half times length of parameres; apex behind humeral angles, feebly explanate medially with ventral angulate projection; width uniform then moderately arcuate to apex; apex behind 5th throughout most of length, tapering basally and interval feebly angled before becoming abruptly at junction with parameres, wider than parameres rounded to suture; serial punctures very coarse, at junction; basoventral opening terminal. deep, on disc separated by slightly more than one- Apicoventral space of phallobase sagittate with third width of a puncture, those in apical third rounded basal lobes, space widest at junction becoming smaller and denser; serial puncture rows of parameres and phallobase and narrowing to appear to be feebly doubled and spaced closer acuminate angulation. Parameres, in dorsal view, between even intervals, punctures nearly touching symmetrical, widest at base, tapering in basal two- across odd numbered intervals; setae on intervals thirds, widening into rounded projections then same as on head and pronotum, and regularly tapering to apex; in lateral view, tapering toward arranged in close linear series, setae often obscured apex, ventral surface weakly concave medially, by metallic reflections; sutural interval subcostate, dorsal surface with highest elevation immediately wider than others at base, becoming gradually, beyond junction with phallobase; apices slightly slightly wider posteriorly and costate on apical reflexed. Aedeagus seven-eighths length of third; remaining intervals narrow, separated on parameres; in lateral view, with two swellings on disc by slightly more than twice their width, even dorsal surface, swelling at junction of phallobase intervals on basal two-thirds unevenly costate or and paramere equal in elevation to paramere, raised above odd intervals as follows: 2nd interval decreasing in elevation to second swelling, which unequally subcostate on basal third, then interrupted is half the elevation of basal swelling, then tapering worthington et al. 189 to narrow, tubular process. One-fifth of aedeagus Stone Co. 11 mi E Perkinston, Red Creek [MEM]; extending beyond dorsal surface of parameres. Red Creek x Hwy 15 [UMIC], and Winston Co. Aedeagus forked in apical eighth, tines thin, nearly Noxubee NWR, T16N, R14E, Sec. 13SE [MEM]; converging at apices; posterior process extending Noxubee NWR, 33°13’59”N, 88°49’42”W [MEM]; three-fourths length of apicoventral space of Noxubee NWR, 33°14’29”N, 88°49’03”W [MEM]; phallobase, forked in apical half. Noxubee NWR, 33°16’56”N, 88°49’12”W [MEM]; Female — Indistinguishable from males. Tombigbee NF, 33°11’50”N, 89°03’20”W [MEM]; Variation — Specimens vary in length from Noxubee NWR, 33°13’44”N, 88°54’34”W [MEM]; 2.53–4.03 mm and in width from 1.09–1.48 mm. Noxubee NWR, 33°13’48”N, 88°54’28”W [MEM]. Metallic reflections typically variable. Minor Seasonal Distribution — Late February differences in depth of pronotal foveae and through mid-November. punctation density are apparent. Diagnosis — This species most closely Distribution — Outside of Mississippi, resembles H. excavatus and H. inaequalis Hydrochus jaechi is known from five male externally. The larger size and granulate surface specimens: one from Florida, two from Louisiana, at the anterolateral margins of the pronotum help and two from Texas (Epler 1996, 2010; Hellman to differentiate H. jaechi from H. excavatus and 1975; Makhan 1995a). The species is relatively H. inaequalis, but positive identification requires common in Mississippi, including localities in the examination of male genitalia. Coastal Meadows (I), Southern Pine Hills (II), Biology — Hydrochus jaechi has been collected Jackson Prairie (III), North-Central Hills (VI), from creeks, lakes, rivers, swamps, bottomland Flatwoods (VII), Pontotoc Ridge (VIII), Black hardwood forest, mixed mesic forest, pine forest, Prairie (IX), and Tombigbee and Tennessee River and in a Jackson prairie remnant using mercury Hills (X) physiographic regions (Fig. 17). vapor lights, flight intercept traps, and black lights. Material Examined — We have examined 176 Notes — Hydrochus jaechi was described specimens from Mississippi localities, including: as “Hydrochus caumatis” Hellman (1975) in his Covington Co. Okatoma River, near Lux [UMIC], dissertation, this species was keyed as Hydrochus Forrest Co. 5 mi S Brooklyn [UMIC], Greene Co. sp. 8 in Epler (1996, 2010). Stateline [MEM], Hancock Co. Stennis Space Center [UMIC]; 1 mi SSW Lakeshore [UMIC]; Hydrochus falsus Hellman n. sp. 4 mi NW Kiln [UMIC], Harrison Co. 3.5 mi NE urn:lsid:zoobank.org:act:45C401DC-41E5-40BA- Saucier [UMIC], Kemper Co. 2 mi N Scooba, 8466-67C01F621886 T12N, R18E, Sec. 29,30 [MEM], Lamar Co. 5 mi N Baxterville [UMIC, MEM], Madison Co. Lake Holotype — Male, bearing label data, stated Barnett, NE of Jackson [MEM], Marion Co. Lake verbatim, with line breaks indicated by “/” and Columbia [UMIC], Noxubee Co. Noxubee NWR, separate labels indicated by “[]”: “[Crescent/ City 33°16’24”N, 88°46’08”W [MEM]; Noxubee NWR, Fla] [Coll Hubbard/ & Schwarz]”, deposited in the 33°15’22”N, 88°47’46”W [MEM]; Noxubee NWR, National Museum of Natural History, Smithsonian 33°15’31”N, 88°46’03”W [MEM]; Noxubee NWR, Institute . 33°14’04”N, 88°48’31”W [MEM]; Noxubee NWR, Paratypes — Alabama: Macon Co.: 7.2 miles 33°16’19”N, 88°45’43”W [MEM], Oktibbeha N.W. Huntsboro on Co. 10, 15 February 1970, Co. 3 mi W of Adaton, 33°29’00”N, 88°58’13”W Folkerts and Jordan, 3 male, 2 female (AUEM); [MEM]; T18N, R14E, Sec. 33SE [MEM]; Mississippi: Forrest Co.: P.B. Johnson State Park, Craig Spring [MEM]; Adaton [MEM]; 6 mi SW 23 June 1986, P.K. Lago, 1 female (UMIC), George Starkville [MEM]; 7 mi S Starkville, 33°20’04”N, Co.: 7 mi SSE Lucedale, 26 May 1987, P.K. Lago, 88°49’06”W [MEM]; Noxubee NWR, 33°21’23”N, 6 male, 5 female (UMIC), Jackson Co.: Ocean 88°52’56”W [MEM], Scott Co. Pinkston Hill, Springs, 12 August 1977, S. Hurdle, 1 female 32°16’06”N, 89°23’33”W [MEM], Smith Co. (UMIC), Lamar Co.: 2 mi SW Bellevue, 8 March Bienville NF, 32°10’06”N, 89°20’54”W [MEM], 1973, Folkerts & Jordan, 1 male, 1 female (AUEM), 190 hydrochidae of Mississippi

Oktibbeha Co.: 1.2 mi SE of Adaton, 33°28’05”N, then straight and moderately narrowed to base 88°54’18”W, 8 August 1996, T.L. Scheifer, 1 behind middle; posterior margin moderately arcuate male (MEM), Scott Co.: Harperville, 28 February medially; punctures very dense, very coarse, deep, 1988, S. Testa, 1 male (UMIC); Georgia: “Geo” somewhat regular in size, nearly equal in size to [Georgia], 43 specimens (not sexed) (USNM); those on elytra, most punctures on disc separated Florida: Crescent City (same label as holotype), by nearly one-half width of puncture, becoming 4 male, 3 female (USNM); Texas: Belfrage, F.C. slightly closer and smaller toward anterior and Bowditch, 2 male, 1 female (MCZ). lateral margins; discal surface uneven and slightly Male — Sub-elongate, rather broad; maximum elevated on apical half, then behind median fovea length 3.6 mm, maximum width 1.2 mm; maximum flattened and less convex than on apical half. width of head across eyes 0.8 mm, minimum Anterolateral foveae small, very shallow, open to interocular distance 0.6 mm; maximum length anterior margin of pronotum; median fovea very of pronotum 0.8 mm, maximum width 0.9 mm, prominent, moderately deep, somewhat elongate, minimum width near base 0.8 mm, maximum length equal to one-third length of pronotum at midline; of elytra 2.5 mm. mediolateral foveae moderately deep, somewhat Dorsum shiny, head piceous, pronotum and rounded, and much smaller than median fovea; elytra brown with apices of elytra much paler, basomedial foveae indistinct; basolateral foveae with metallic gray, green, blue-green and purple small, much deeper and closer to adjacent margins reflections obscuring most ground color. Mentum of pronotum than anterolateral foveae; base of and submentum shiny rufopiceous with same pronotum on midline irregularly and slightly metallic reflections as on dorsum. Antennae and depressed. palpi brown with ultimate segment of maxillary Elytron moderately strongly convex, sub- palpomere slightly darkened. Legs brown with elongate, moderately broad; lateral margin feebly tibiofemoral joints only very narrowly piceous or explanate medially then moderately arcuate to dark brown. apical third and feebly constricted subapically; Head across eyes slightly less than width of apices subtruncate; serial punctures very coarse, pronotum; clypeal punctures very dense, moderately deep, those on disc very regular and separated by coarse, those near base very similar to punctures nearly one-third width of a puncture; punctures in on interocular region, midline of disc feebly apical fifth and in last three serial rows gradually raised; epistomal sulcus indistinct; interocular becoming smaller and closer nearing margin; region unevenly raised on midline and rugose; sutural interval near base only slightly wider than mid-cranial depression indistinct; submedial other intervals, very slightly wider and subcostate interocular depressions foveate, foveae deep and on apical third; remaining intervals on elytron large with closer punctures than on surrounding narrow, separated on disc by nearly twice their elevated areas of disc, several punctures nearly width, most intervals appear uniformly narrowed coalesced; remaining punctures on disc moderately and regular in height, except as follows: even large, regular in size and spacing, most separated numbered intervals perceptibly more convex than by less than width of a single puncture; mid- odd numbered, 4th interval slightly broadened and occipital region broadly elevated near base of head. very briefly costate on beginning of the apical third, Mentum finely, densely punctate, basal half of disc 6th interval with a small costa just behind middle moderately deeply foveate medially; submentum and anterior to and only slightly less prominent than more finely punctate than mentum, disc non- costa on 4th interval; 7th interval near middle slightly foveate. sinuate and nearly coalesced with 8th; 8th interval Pronotum moderately convex, slightly wider unevenly raised on basal two-thirds, and slightly than long, widest just behind anterior angles; more prominently raised and swollen medially; anterior margin slightly arcuate; lateral margins epipleuron impunctate and only feebly impressed in only feebly and narrowly inflexed in apical half; basal half. Figure 18. sides viewed above subparallel on apical fourth, Venter with dense hydrofuge pubescence worthington et al. 191 throughout, with additional long, curved, Mississippi, with collection localities in the Coastal fine, sparse yellow setae; long setae sparse on Meadows (I), Southern Pine Hills (II), Jackson prosternum, increasing in density posteriorly. Prairie (III), North-Central Hills (VI), Flatwoods Prosternum irregularly foveate, moderately densely (VII), Pontotoc Ridge (VIII), and Black Prairie (IX) punctate. Mesosternum and metasternum coarsely (Fig. 20). punctate, irregularly foveate. Metasternum convex Material Examined — We have examined 17 medially. Coxae, trochanters, femora (in basal specimens from Mississippi localities. including: fourth) bearing dense hydrofuge pubescence. Legs Forrest Co. P.B. Johnson State Park [UMIC], bearing curved, recumbent, fine yellow setae; legs George Co. 7 mi SSE Lucedale [UMIC], Jackson with metallic reflections above dense hydrofuge Co. Ocean Springs [UMIC], Lamar Co. 2 mi SW pubescence. Bellevue [AUEM], Oktibbeha Co. 1.2 mi SE of Male genitalia. Figure 19. Phallobase two Adaton, 33°28’05”N, 88°54’18”W [MEM], and times length of parameres; apex round and closed; Scott Co. Harperville [UMIC]. phallobase widest medially, tapering to base and Seasonal Distribution — Late February junction with parameres, wider than parameres through mid-August. at junction with phallobase; basoventral opening Diagnosis — The absence of an epicranial subapical. Apicoventral space widest at junction suture will separate H. falsus from all other of parameres and phallobase and narrowing to Mississippi species except H. callosus and H. acuminate angulation. Parameres symmetrical, jiawanae. Hydrochus falsus is much smaller in widest at base, tapering to apex, apices diverging; in size, both length and width, than H. callosus. lateral view, tapering toward apex, ventral surface Hydrochus jiawanae and H. falsus are nearly entirely concave to apex, thus appearing deflexed, identical, including genital structure. Hydrochus concavity entirely smooth, lacking projections or falsus possesses rounded elytral sutural angles, but notches; apices straight (usual) or slightly reflexed in some specimens the angles appear to be right (rarely). Aedeagus one-half length of parameres; angled. Hydrochus jiawanae has elytral sutural in lateral view, dorsal surface rounded medially, angles that are produced slightly, thus appearing tapering at the junction of phallobase and parameres acute. Male genitalia are nearly identical in both and at apex, apex with a short acuminate process species, however H. falsus lacks a subapical notch ventrally; aedeagus greatly constricted at junction in the concavity on the ventral surface of the with phallobase. Two projections of aedeagus parameres, when viewed laterally, which is present extending posteriorly into apicoventral space of in H. jiawanae. Examination of male genitalia phallobase. should be done in order to accurately separate these Female — Indistinguishable from males. species. Variation — Specimens vary in length Biology — Hydrochus falsus has been collected from 2.7–3.5 mm and in width from 0.9–1.4 at black lights, but specific aspects of the species’ mm. Reflective coloration of the elytra can vary biology remain unknown. Aquatic habitats present considerably in specimens of H. falsus. Some at Mississippi collection sites include a large specimens exhibit a more shallowly, broadly river (the Pascagoula), a fairly large recreational depressed submentum, while other individuals are impoundment and a slough. clearly foveate. Notes — Hydrochus falsus was keyed as Etymology — ‘falsus’ Latin, deceive. Named Hydrochus sp. 1 in Epler (1996, 2010). in reference to the similarity of morphological characteristics and general appearance shared with Hydrochus jiawanae Makhan, 1996 H. prolatus. Distribution — Hydrochus falsus ranges from Hydrochus jiawanae Makhan 1996: 184. Georgia and Florida west to Texas and northward through the Mississippi River Valley to Indiana. Description — Holotype Male--Elongate, The species occurs mostly in the southern third of broad; maximum length 2.77 mm, maximum width 192 hydrochidae of Mississippi

1.11 mm; maximum width of head across eyes pronotal margin. 0.63 mm, minimum interocular distance 0.4 mm; Elytron moderately convex, apical third maximum length of pronotum 0.65 mm, maximum gradually sloping to apex; lateral margins width 0.7 mm, minimum width near base 0.58 mm, moderately constricted on basal third, then maximum length of elytra 1.81 mm. moderately arcuate medially to apical third Dorsum shiny with light green, blue-green, and moderately constricted preapically; apex scattered purple and blue reflections obscuring subtruncate, feebly explanate and produced near nearly all ground color; ground color of head suture; sutural angle acute; serial punctures coarse, piceous, pronotum and elytra brown. Mentum and deep, those on disc regular, separated by one-third submentum shiny rufopiceous. Antennae and palpi width of a puncture, becoming gradually smaller reddish brown with apex of ultimate maxillary and denser on apical third; serial rows 7, 8, 9, and palpomere piceous. Legs reddish brown with 10 slightly more impressed than others; sutural tibiofemoral joints and apical fourth of ultimate interval near base slightly wider than others, tarsomeres piceous. gradually becoming wider and costate on apical Head across eyes equal to width of pronotum; third; intervals narrow, separated on disc by one clypeus slightly more convex on midline, punctures and one-third their width, slightly convex, and moderately fine, dense, very similar to those on regular in height except as follows: 4th, 6th, and interocular region; epistomal sulcus lacking; 8th intervals near margin in apical third becoming interocular region very uneven, only slightly gradually more convex; 4th interval perceptibly elevated to vertex; mid-cranial depression lacking; wider and subcostate at beginning of the apical submedial interocular depressions broadly foveate; third; 6th interval very feebly raised and broadened punctures moderately coarse, irregularly spaced, just behind middle, and slightly raised anterior to most separated by less than width of a puncture subcosta on 4th interval; 7th interval near middle to nearly coalesced; mid-occipital region not sinuate and nearly coalesced with 8th interval; constricted. Mentum finely, moderately densely 8th interval on basal half irregularly raised above punctate; basal half of disc broadly, deeply foveate others, and perceptibly broader near middle; medially; submentum more finely and sparsely epipleuron impunctate, smooth. punctate than mentum; disc with two small, deep, Male genitalia. Figure 21. Phallobase two foveal pits. and one-fourth times length of parameres; apex Pronotum quadrate in form, convex, apical round, closed; widest medially, tapering to base half widest; anterior margin feebly arcuate; lateral and junction with parameres, wider than parameres margins only feebly inflexed in apical half; sides at junction with phallobase; basoventral opening viewed above shallowly sinuate, apical half subapical. Apicoventral space of phallobase widest subparallel, then shallowly incurved behind middle immediately behind junction of parameres and and slightly narrowed to base; posterior margin phallobase and narrowing to acuminate angulation. moderately arcuate; disc rugose on basal half, Parameres symmetrical, widest at base, tapering rather flat on midline; punctures moderately coarse, to apex, apices nearly contiguous; in lateral view, rather regular in size, irregularly spaced with most tapering toward apex, ventral surface entirely punctures separated by less than one-half width of concave to apex, appearing deflexed, ventral a puncture, only slightly denser and finer toward concavity with subapical notch in apical third anterior and anterolateral margins. Anterolateral of paramere; apices straight (usual) or slightly foveae indistinct; median fovea prominent, shallow, reflexed (rarely). Aedeagus two-thirds length of somewhat round, equal to slightly more than one- parameres; in lateral view, apical half of dorsal fourth length of pronotum at midline; mediolateral surface flattened, apex a concavity with short foveae irregularly round, only slightly shallower acuminate process at ventral surface; aedeagus than median fovea; basomedial foveae indistinct; greatly constricted at junction with phallobase. Two basolateral foveae small, deep, with posterior projections of aedeagus extend posteriorly into margin open and nearly confluent with posterior apicoventral space of phallobase. worthington et al. 193

Female — Indistinguishable from males. habitats that produced specimens included small to Variation — Specimens vary in length from medium black water rivers and woodland ponds. 2.6–3.9 mm and in width from 1.1–1.3 mm. Ground Notes — Hydrochus jiawanae was described color may vary from piceous to dark reddish brown. as “Hydrochus prolatus” by Hellman (1975) in his Metallic variation on elytra varies in intensity. dissertation. This species was keyed as Hydrochus Punctures on head, pronotum, and elytra may be sp. 2 in Epler (1996, 2010) and Ciegler (2003). closer together than herein described. Mediolateral and median foveae may be indistinct in some Hydrochus pajnii Makhan, 2000 individuals. The depth of small depressions on the submentum varies from indistinct to very shallow Hydrochus pajnii Makhan 2000: 51. and broad. Distribution — Hydrochus jiawanae ranges Description — Holotype Male--Elongate; from Vermont to Florida and west to Texas. In maximum length 3.13 mm, maximum width 1.1 Mississippi, this species seems restricted to the mm; maximum width of head across eyes 0.7 mm, southeastern counties in the Coastal Meadows (I) minimum interocular distance 0.41 mm; maximum and Southern Pine Hills (II) regions (Fig 22). length of pronotum 0.74 mm, maximum width 0.74 Material Examined — We have examined 37 mm, minimum width near base 0.6 mm; maximum specimens from Mississippi localities, including: length of elytra 2.05 mm. George Co. Lucedale, Hancock Co. 4 mi NW Kiln Dorsum dull, head piceous, pronotum and [UMIC]; 6 mi WNW Waveland [UMIC], Harrison elytra brown, ground color nearly obscured by Co. 3.5 mi NE Saucier [UMIC]; 2 mi N Lyman metallic green and faint scattered violet reflections. [UMIC]; 13 mi E Saucier [UMIC], and Stone Co. Mentum and submentum rufopiceous with same Red Creek x Hwy 15 [UMIC]; U.M. Forestlands metallic reflections as dorsum. Antennae and palpi [UMIC]. yellow-brown with apex of ultimate maxillary Seasonal Distribution — Late February palpomere piceous. Legs yellow-brown with through early July. tibiofemoral joints and apex of ultimate tarsomeres Diagnosis — The base of the epicranial suture piceous. is normally absent, although in some specimens, Head across eyes imperceptibly wider than it is vaguely indicated, but lateral arms are absent. width of pronotum; clypeal punctures moderately The absence of an epicranial suture will separate coarse, exceedingly dense, much closer than on most specimens of H. jiawanae from all other interocular region with many nearly coalesced; Mississippi species, except H. callosus and H. coarse punctures interspaced with numerous, falsus. Hydrochus jiawanae is much smaller in nearly imperceptible fine setae; epistomal sulcus size, both in length and width, than H. callosus. fine laterally, gradually broadened and moderately Hydrochus jiawanae and H. falsus are nearly impressed toward middle; interocular region identical externally and internally. Hydrochus behind epistomal sulcus gradually, irregularly jiawanae has elytral sutural angles that are produced raised to vertex; mid-cranial depression short, slightly, appearing acute, while in Hydrochus falsus deeply sulcate and coarsely punctate, punctures the sutural angles are rounded, although some coalesced; submedial interocular depressions vague; specimens have these nearly right angled. Male elevated areas of disc near vertex somewhat more genitalia are near identical in both species; however, sparsely and irregularly punctate than surrounding H. falsus lacks a subapical notch in the concavity on integument; most punctures moderately large, very the ventral surface of the parameres when viewed irregularly but very closely spaced, many nearly laterally, while a notch is present in H. jiawanae. coalesced. Mentum finely, very densely punctate, Examination of male genitalia is essential for basal half of disc moderately, deeply foveate positive identification. medially; submentum sparsely, finely punctate, with Biology — Nothing has been published disc nearly completely covered by two large, deep concerning the biology of H. jiawanae. Mississippi foveae. 194 hydrochidae of Mississippi

Pronotum convex, very slightly wider than raised, with only a short, narrow costate area on th long, apical half widest; anterior margin straight; middle; 7 interval near middle slightly sinuate th lateral margins moderately strongly inflexed; and nearly coalesced with costa on 8 interval; inflexed sides narrow and irregularly punctate, epipleuron moderately coarsely punctate, punctures punctures shallow, fine; sides viewed from above shallow, occasionally nearly coalesced. round, moderately, densely crenate, moderately Male genitalia. Figure 23. Phallobase less than sinuate in outline, with apical half subparallel, then half total length of genitalia; apex round; phallobase slightly incurved behind middle and moderately approximately uniform in width throughout, narrowed to base; posterior margin moderately, subequal to width of parameres; basoventral strongly arcuate medially; punctures moderately opening terminal. Apicoventral space of phallobase coarse, irregular, dense punctures on disc separated widest at junction of parameres and phallobase by nearly one-third less width of puncture, denser and narrowing to obtuse angulation. Parameres and finer toward lateral margins; elevated areas of symmetrical, widest at base, narrowing in anterior disc medially adjacent to foveae occasionally more third, outer margins convex; in lateral view, tapering sparsely punctate than surrounding integument; towards apex, ventral surface concave to apical setae tiny and indistinct. Anterolateral and fourth, then flat to apex; apices straight. Aedeagus basolateral foveae similar, moderately deep, small long, two-thirds length of parameres, in lateral view, and slightly open to adjacent pronotal margin; with two dorsal swellings, basal swelling larger, median and mediolateral foveae round, deep located at junction of phallobase and parameres, with median fovea equal to one-fourth length of second swelling subequal to basal swelling. pronotum at midline; basomedial foveae elongate, Aedeagus greatly constricted beyond secondary deep and convergent near base. swelling, tapering gradually to apex; apical two- Elytron strongly convex, elongate; lateral fifths of aedeagus extending above dorsal surface margin slightly constricted and straight on basal of parameres; aedeagus, in dorsal view, between third, then moderately arcuate medially to apical parameres, deeply forked, fork originating beyond third where feebly constricted subapically; apex base of parameres; aedeagus extending posteriorly nearly imperceptibly angled behind 4th interval, three-fourths apicoventral space of phallobase, then sharply rounded to suture; serial punctures forked in apical half. coarse, deep, those on disc separated by nearly Female — Indistinguishable from males. one-third width of a puncture, those in apical third Variation — Specimens vary in length from becoming gradually smaller and denser; setae on 2.7–3.6 mm and in width from 1.1–1.3 mm. Dorsal intervals obscured by metallic reflections; basal metallic reflections vary from green, blue-green to half of sutural interval flat and only slightly wider golden green and occasionally violet. Specimens than other intervals, posteriorly becoming gradually lacking metallic reflections are rare, but do occur. wider and costate on apical third; remaining The elytra may be maculate. The maculae, when intervals on elytron narrow, most separated on disc present, are generally irregular, large, reddish brown by one and one-third their width; several intervals or rufopiceous. The largest and most consistent nd rd appear unequally raised as follows: 2nd interval on macula is located on 2 and 3 intervals just before rd basal third subcostate and more strongly raised than middle and anterior to costa on 3 interval. The th th any other interval at base; 3rd interval moderately, second largest macula is centered on 4 and 5 strongly costate from midlength to the beginning of intervals in a small median depression just anterior th apical third; 4th interval unevenly raised in basal half to callus on 4 interval. but decidedly costate just before middle, costa same Distribution — Hydrochus pajnii occurs from height as costate area on 3rd interval; 4th interval Maryland south to Florida, west to Texas and north then interrupted and flattened behind midlength to through the Mississippi River basin as far as Illinois where slightly callused on the beginning of apical and Indiana. This species is known from scattered third; 6th interval feebly raised just anterior to callus localities in every physiographic region, except the on 4th interval; 8th interval unequally and slightly Coastal Meadows (I) and Paleozoic Bottoms (XI) worthington et al. 195

regions of Mississippi (Fig. 24). Hydrochus schereri Makhan, 1995 Material Examined — We have examined 18 specimens from Mississippi localities, including: Hydrochus schereri Makhan 1995a: 20. Adams Co. Natchez [UMIC], Clay Co. 5 mi W West Point [UMIC], George Co. 12 mi SW Lucedale Description — Male--Moderately small, [UMIC]; 3.2 mi S, 1.8 mi E Benndale [MEM], elongate; maximum length 2.8 mm, maximum Jasper Co. 6 mi NW Montrose [UMIC], Noxubee width 1.0 mm; maximum width of head across eyes Co. Noxubee NWR [MEM]; Noxubee NWR, 0.7 mm, minimum interocular distance 0.4 mm; 33°16’24”N, 88°46’04”W [MEM]; Noxubee NWR, maximum length of pronotum 0.6 mm, maximum 33°16’19”N, 88°45’43”W [MEM]; Noxubee NWR, width 0.7 mm, minimum width near base 0.65 mm; 33°16’23”N, 88°46’03”W [MEM], Oktibbeha maximum length of elytra 1.9 mm. Co. Dorman Lake [MEM], Sharkey Co. Delta NF, Dorsum shiny; head piceous, pronotum and 32°52’39”N, 90°45’36”W [MEM]; Rolling Fork elytra reddish brown with pronotum slightly paler [UMIC], and Washington Co. Stoneville [MEM]. near anterior and posterior margins, ground colors Seasonal Distribution — Most records from generally obscured by green and golden green April through August, with one collection in metallic reflections. Mentum and submentum November. rufopiceous with scattered metallic reflections Diagnosis — Hydrochus pajnii possesses similar to those on dorsum. Antennae and palpi distinctive genitalia and examination of them reddish brown with apex of ultimate maxillary is necessary for positive identification, see palpomere darkened or piceous. Legs reddish brown diagnosis of H. excavatus. Externally H. pajnii with tibiofemoral joints and apex of tarsi piceous. closely resembles H. inaequalis and H. excavatus. Head across eyes equal to pronotum, clypeal Hydrochus pajnii generally can be distinguished punctures moderately coarse, dense, very irregularly by its larger size, more prominent elytral calli, spaced and irregularly coalesced near base; fine and reduced cranial and pronotal punctation in setae obscured by metallic reflections; epistomal comparison to either H. inaequalis or H. excavatus. sulcus very fine laterally, gradually broadened Additionally, Hydrochus pajnii often has coalesced and moderately, deeply impressed on middle half, epipleural punctures, while in H. excavatus the coarse punctures within depression coalesced; epipleural punctures are arranged in a single series. interocular region very rugose, medially behind Biology — Hydrochus pajnii has previously epistomal sulcus very gradually, irregularly raised been collected at ponds, rivers, streams, ditches, to vertex; mid-cranial depression deeply sulcate and and at ultraviolet lights (Ciegler 2003). Specimens coarsely punctate, punctures coalesced; submedial collected during this study were found mostly at interocular depressions very irregular, deep, with black lights placed near swamps and a large river, punctures nearly coalescent; discal elevated areas as well as various aquatic habitats in pine woods, punctate; punctures moderately large, generally mixed forest, and bottomland hardwood forests. much larger than on clypeus, very irregularly spaced Notes — Hydrochus pajnii was described as with most separated on disc by less than one-half “Hydrochus undulatus” by Hellman (1975) in his width of a puncture; setae same as on clypeus; mid- dissertation. “Hydrochus undulatus” Hellman is occipital region broadly, moderately constricted nomina nudum as it was ascribed to Hellman in between posterolateral margins of eyes. Mentum White et al. 1985: 363 (Hansen 1999). The locality finely, densely punctate, basal two-thirds of disc information published in the original description moderately, deeply foveate medially; submentum of Hydrochus pajnii Makhan (2000) was incorrect very sparsely punctate with disc nearly completely (Short & Hebauer 2006) and should have read “Ill. obscured by two large, very deep, transverse foveae. Ham. Co./5.2 mi N., 1.8 mi E./McLeansboro/VIII- Pronotum moderately convex, slightly 16-1969 Bk. Lt./ J.K. Bouseman”. This species was wider than long, widest in apical half; anterior keyed as Hydrochus sp. 5 in Epler (1996, 2010) and margin straight; lateral margins narrowly, sharply Ciegler (2003). inflexed in basal two-thirds; inflexed surface with 196 hydrochidae of Mississippi

a single row of moderately fine punctures; sides with ventral surface flattened, dorsal surface with of pronotum viewed from above angulate, feebly three swellings, basal swelling subequal in elevation crenulate, sinuate, with apical half parallel, then to dorsal surface of paramere, second swelling slightly incurved behind middle and moderately medial on aedeagus subequal to basal swelling narrowed to base; posterior margin moderately in elevation, preapical swelling minute; in dorsal arcuate; punctures coarse, dense, very irregularly view, forked in apical third. At base, aedeagus with spaced with most separated on disc by one-fourth posterior process extending half of apicoventral to one-third their width, denser and finer toward space of phallobase, process bifurcate in apical lateral margins; elevated areas punctate similar third. to surrounding discal surface. Anterolateral Female — Indistinguishable from males. and basolateral foveae very shallow; median, Variation — Specimens vary in length from mediolateral and basomedial foveae shallow. 2.2–2.8 mm and in width from 0.8–1.1 mm. As Elytron convex, elongate; lateral margin might be expected, variation in metallic coloration slightly constricted in basal two-fifths, then occurs. moderately arcuate to apex; apex rounded to Distribution — Hydrochus schereri occurs suture; serial punctures deep, large, those on disc from Massachusetts south to Florida and as far regular, separated by one-third their width, those west as Mississippi. Like, H. jiawanae, this in apical third and in rows 8, 9, and 10 gradually species occurs in the most southeastern counties becoming smaller and denser nearing the elytral in Mississippi (Coastal Meadows (I) and Southern margin; sutural interval near base slightly wider Pine Hills (II) physiographic regions) (Fig. 26). than other intervals, then posteriorly becoming Material Examined — We have examined gradually, slightly wider and moderately costate on 41 specimens from Mississippi localities, apical third; remaining intervals on elytron appear including: George Co. Mixon Lakes, 30°50’28”N, feebly convex, regular in height except as follows: 88°43’11”W [MEM], Hancock Co. Stennis Space 2nd interval slightly more convex on basal fourth; Center [UMIC], Harrison Co. 8 mi NE Saucier 4th interval slightly widened and slightly raised [UMIC], Jackson Co. Grand Bay Savannah, on beginning of apical third; 7th interval medially 30°27’31”N, 88°25’14”W [MEM]; MS Sandhill sinuate and nearly coalesced with 8th interval; 8th Crane NWR, 30°27’34”N, 88°41’28”W [MEM], interval feebly more convex than adjacent odd and Stone Co. T4S-R1W Sec. 6 [UMIC]; Red Creek numbered intervals and medially raised where x Hwy 15 [UMIC]. nearly coalesced with 7th interval; epipleuron Seasonal Distribution — April through June, moderately, coarsely punctate on basal three- August and early September. fourths, punctures moderately deep near base then Diagnosis — Hydrochus schereri most closely becoming gradually shallower until disappearing on resembles H. simplex. Hydrochus schereri usually apical half. possesses more prominent elytral calli on the 4th Male genitalia. Figure 25. Phallobase interval, while H. simplex lacks raised calli entirely. approximately one and one-half times length This diagnostic feature is generally unreliable on of parameres; apex round; phallobase concave its own, due to variability between species, and when viewed laterally, widest in posterior third, positive identification requires examination of the at narrowest point less than width of parameres male genitalia. Hydrochus simplex possesses a at base; basoventral opening terminal, appearing phallobase two-thirds the length of the parameres, cordate. Apicoventral space of phallobase widest at while H. schereri has a phallobase one and one half junction of parameres and phallobase and narrowing times the length of the parameres. to acuminate point. Parameres symmetrical, widest Biology — Hydrochus schereri has previously at base, narrowing towards apex, widened at apical been collected in streams and at ultraviolet lights. two-fifths length, then gradually tapering to apex, Specimens were collected during this study near sides of paramere sinuate; apices straight. Aedeagus ponds in coastal savannah at sun lamps, mercury three-fourths length of parameres; in lateral view, vapor light, and black lights, and at black lights worthington et al. 197 set near Red Creek, a moderately large, sandy breaks indicated by “/”: “Md. CalvertCo/Dunkirk/ bottomed, blackwater river. IX-29-1968/ J.L. Hellman”, is deposited in the Notes — This species was described as National Museum of Natural History, Smithsonian “Hydrochus woodi” by Hellman (1975) in his Institute. dissertation and was keyed as Hydrochus sp. 6 in The holotype and twenty-three paratypes Epler (1996, 2010) and Ciegler (2003). of H. daviniaae Makhan, 1995a, were examined from the Naturhistorisches Museum, Wien, Notes on extralimital species Austria (NHMW). The spelling as Hydrochus daviniae Makhan (1995b) stands as an unjustified The poor quality of genitalic illustrations emendation to Hydrochus daviniaae Makhan produced by Makhan in his descriptions of (Hansen 1999). All specimens were from five Hydrochus species descriptions prompted us to Texas localities. The holotype male and three male examine several Makhan types with distributions paratypes were examined and found to be typical that overlapped those of Mississippi species. representatives of Hydrochus vagus LeConte, and Makhan (2004a) described Rishihydroius soesae thus H. daviniaae should be considered a junior from Rhode Island. Short and Hebauer (2006) synonym of H. vagus. The label data for the subsequently synonymized the genus Rishihydroius holotype male, stated verbatim, with line breaks with Hydrochus, thus creating a new combination designated by “\”: “USA-TEXAS 1991\Santa Ana Hydrochus soesae (Makhan). The examination WR\S Mc Allen (4)\20./21.XI. lg. Jäch”. The twenty of the type of Hydrochus (Rishihydroius) soesae paratype females contained series of three different (Makhan) was not possible as the specimen has not species. Makhan’s illustration of the male genitalia been deposited in the Peabody Museum as indicated provide no aid in identification.Hydrochus vagus by Makhan (2004a). Correspondence with curators LeConte is externally most readily confused with H. at Peabody Museum of Natural History, Yale simplex LeConte in the U.S. However, H. simplex University, New Haven, Connecticut indicated LeConte possesses a punctate epipleuron, while that they do not possess nor have they received the epipleuron of H. vagus LeConte is impunctate. any types of this species. We have contacted the Examination of the male genitalia, which are author in an attempt to locate the type, but have very distinctive, is required to confirm proper received no correspondence. We assume the types identification. are still possessed by the author, or deposited The male holotype of H. bakkeri Makhan, at another institution, or lost. A combination of 1995a, from the Naturhistorisches Museum, Wien, the locality information (NE United States), the Austria (NHMW) was examined and is clearly a written description and the general characters of male of H. obscurus Sharp, thus Hydrochus bakkeri the illustrated male genitalia (Makhan 2004a, Fig. Makhan should be considered a junior synonym. 2), however poor, has lead us to believe that the The label data, stated verbatim, with line breaks holotype is a typical form of Hydrochus scabratus designated by “\”: “USA – TEXAS 1991\Santa Mulsant and should be considered a junior Ana WR\S McAllen (4)\20./21.XI. lg.Jäch”. This synonym. Two unsuccessful attempts (1975 & is a new country record and range extension for H. 2016) were made to locate the type of H. scabratus. obscurus Sharp of approximately 400 miles north The holotype is not in the Mulsant collection of its currently known range, which extends from in Paris (MNHN). The holdings at Musée des the Mexican state of San Luis Potosi to Argentina Confluences, Lyon, France were also searched after (Hellman 1975; Oliva 1996). Examination of indications that syntypes of some Mulsant material male genitalia is necessary for identification. A may have been deposited there when Mulsant lived combination of the following characteristics will in Lyon (pers. comm. A. Mantilleri), but no type separate H. obscurus from all other U.S. Hydrochus: material was found. The holotype is deemed lost 1) parameres weakly sagittate near apex, 2) or destroyed, and a neotype is here designated. The genitalia lacking pseudoparameres, 3) basoventral neotype male with label data, stated verbatim, line opening terminal with four-sided, shield-like 198 hydrochidae of Mississippi

projection extending from phallobase and 4) and Max Barclay at the Natural History Museum sclerotized portion of aedeagus truncate at apex. of London, Bernd Jaeger at Berlin Natural History Makhan (2004a) stated that the holotype of Museum, Antoine Mantilleri at Museum National Hydrochus jasodae Makhan was deposited in two d’Histoire Naturelle-Paris, Harold Labrique at museums, the Illinois Natural History Survey, Musée des Confluences-Lyon, France, Raymond Champaign, Illinois, USA and Museum National Pupedis at Peabody Museum of Natural History- d’Histoire Naturelle, Paris, France. The holotype, Yale University, and Manfred Jäch and Michaela a female, which we examined, is deposited in the Brojer at the Natural History Museum of Austria former collection. for the loan of types, additional specimens, Hydrochus foveatus Haldeman lacks a and valuable input. Joe McGowan is gratefully holotype. Haldeman (United States et al. 1852) acknowledged for his assistance in imaging did not designate a holotype of H. foveatus and specimens. We thank JoVonn Hill for his editorial subsequent authors have not dealt with this issue. assistance and two anonymous reviewers for There is a single female specimen in the LeConte providing valuable feedback on this manuscript. collection bearing the following label data (given verbatim with line breaks indicated by “/”): “H. LITERATURE CITED foveatus Hd./Ft. Gates Texas.” After comparison of the female with Haldeman’s original description Arnett RH Jr (1983) Checklist of the beetles of of the species, the authors are confident that this North and Central America and the West specimen was used by Haldeman for his description Indies. Vols. 1-10 Florida and Fauna Publs., of the species and so designate this individual Gainesville, FL 2173 pp. as the lectotype. This specimen is deposited in Blackwelder RE (1944) Checklist of the the Museum of Comparative Zoology, Harvard coleopterous insects of Mexico, Central University. America, the West Indies, and South America, Upon examination of the holotype of part 2. Bulletin of the U.S. National Museum Hydrochus monishi Makhan, 1995a, from the 185: 189-341. Naturhistorisches Museum, Wien, Austria Blatchley WS (1928) Notes on some Florida (NHMW), we concluded that it is a typical male of Coleoptera, with descriptions of new species. Hydrochus foveatus Haldeman, thus H. monishi is Canadian Entomologist 60: 60-73. here considered a junior synonym of that species. Brigham WV (1982) Hydrophilidae, pp 10.75- Following is the label data, stated verbatim, with 10.95, in Brigham AR, Brigham WV, Gnilka A line breaks designated by “/”: “USA-TEXAS 1991/ (eds.). The aquatic insects and oligochaetes of Palmetto State P/70km S Austin (13)/26.XI. leg. North and South Carolina. Midwest Aquatic Jach”. The genitalia of the holotype male possess Enterprises, Mahomet, IL xi + 837 pp. pseudoparameres, which are entirely lacking in Ciegler JC (2003) Water Beetles of South Carolina Makhan’s illustration. The sagittate form of the (Coleoptera: Gyrinidae, Haliplidae, parameres, presence of pseudoparameres, and Noteridae, Dytiscidae, Hydrophilidae, collection locality in Texas will separate Hydrochus Hydraenidae, Scirtidae, Elmidae, Dryopidae, foveatus from all other species in the United States. Limnichidae, Heteroceridae, Psephenidae, Ptilodactylidae, and Chelonariidae). Biota of ACKNOWLEDGEMENTS South Carolina, Vol. 3.Clemson University Public Service Publishing, Clemson, SC 207 The authors would like to express their pp. gratitude to Philip Perkins at MCZ, Charyn Micheli Cross RD, Wales RW, Traylor CT (1974) Atlas at the United States National Museum, Terry of Mississippi. University Press, Jackson, Schiefer at Mississippi State University, Charles Mississippi 187 pp. Ray at Auburn University, Chris Grinter at the ESRI (2011) ArcGIS Desktop: Release 10. Illinois Natural History Survey, Christine Taylor Redlands, CA: Environmental Systems worthington et al. 199

Research Institute. Makhan (1998). Latissimus 12: 15. Epler JH (1996) Identification Manual for the Water Leng CW, Mutchler AJ (1918) Insects of Florida. V. Beetles of Florida (Coleoptera: Dryopidae, The water beetles. Bull. Amer. Mus. Nat. Hist. Dytiscidae, Elmidae, Gyrinidae, Haliplidae, 38: 73-116. Hydraenidae, Hydrophilidae, Noteridae, Lowe EN (1915) Mississippi: its geology, Psephenidae, Ptilodactylidae, Scirtidae). geography, soil and mineral resources. Florida Department of Environmental Mississippi State Geological Survey Bulletin Protection, Tallahassee, FL 257 pp. 12: 335 pp. Epler JH (2010) The Water Beetles of Florida Makhan D (1994) Thirty-five new Hydrochus - an identification manual for the families species from the Old and the New World Chrysomelidae, Curculionidae, Dryopidae, (Coleoptera: Hydrophilidae). Annales Dytiscidae, Elmidae, Gyrinidae, Haliplidae, Historico-Naturales Musei Nationalis Helophoridae, Hydraenidae, Hydrochidae, Hungarici 86: 29-42. Hydrophilidae, Noteridae, Psephenidae, Makhan D (1995a) Descriptions of six new species Ptilodactylidae and Scirtidae. Florida of Hydrochus from South and North America Department of Environmental Protection, (Coleoptera: Hydrochidae). Zoological Studies Tallahassee, FL 399 + iv pp. 34: 18-20. Hansen M (1998) The systematic status of Kiransus Makhan D (1995b) Descriptions of ten new species Makhan, 1994, with the description of three of Hydrochus from different parts of the World new species of Hydrochus Leach, 1817 (Coleoptera: Hydrochidae). Phegea 23: 187- (Coleoptera: Hydrochidae). Entomologica 193. Scandinavica 29: 223-232. Makhan D (1996) Descriptions of three new species Hansen M (1999) World catalogue of insects, of Hydrochus (Coleoptera: Hydrochidae). Hydrophiloidea (s. str.) (Coleoptera). Vol. 2 Phegea 24: 183-185. Apollo Books, Stenstrup, Denmark 416 pp. Makhan D (2000) Hydrochidae (Coleoptera) from Hellman JL (1975) A taxonomic revision of the North America with description of Hydrochus genus Hydrochus of North America, Central pajnii sp. nov. and Hydrochus yadavi sp. America, and West Indies. Unpublished Ph.D. nov. Pp 51-53 in: Sobti RC, Yadav JS (eds.). Dissertation, University of Maryland 441 pp. Some aspects on the insight of insect biology. Hilsenhoff WL (1995a) Aquatic Hydrophilidae and Narendra Publishing House, Delhi, India 311 Hydraenidae of Wisconsin (Coleoptera). I. pp. Introduction, key to genera of adults, Makhan D (2001) A new genus, Soesilius, and a and distribution, habitat, life cycle, and new species of Hydrochidae (Coleoptera) from identification of species ofHelophorus America. Russian Entomological Journal 10: Fabricius, Hydrochus Leach, and Berosus 389-393. Leach (Hydrophilidae), and Makhan D (2004a) Hydrochidae of the world, Hydraenidae. Great Lakes Entomologist 28: Dryopidae and Hydrophilidae (Coleoptera). 25-53. Calodema 2:11-26. Hilsenhoff WL (1995b) Aquatic insects of Makhan D (2004b) Two new Hydrochidae Wisconsin: Keys to Wisconsin genera and notes (Coleoptera) species from the world. Acta on biology, habitat, distribution and species. Biologica Universitatis Daugavpiliensis 4: 107- Publication of the Natural History Museums 109. Council, University of Wisconsin-Madison 3: Makhan D (2005) Hydrochus brianbrowni sp. nov. 1-79. (Coleoptera: Hydrochidae), a new American Hubbard HG, Schwarz EA, LeConte JL (1878) The species. Baltic Journal of Coleopterology 5: 63- Coleoptera of Michigan. Proceedings of the 65. American Philosophical Society 17: 593-669. Mississippi Department of Environmental Quality Jäch MA (2000) On two Hydraenidae described by (2013) MS Physiographic Regions 2013. 200 hydrochidae of Mississippi

Available from http://www.maris.state.ms.us/ Thomson CG (1860) Skandinaviens Coleoptera. HTM/DownloadData/Statewide.html (accessed 2:1-304. May 2016). United States Department of Commerce, U.S. Notman H (1919) Coleoptera collected at Mooers, Census Bureau, Geography Division (2014) Clinton Co., N.Y., September 9-13, 1918, with Available from: descriptions of new species. Bulletin of the http://www2.census.gov/geo/tiger/TIGER2014/ Brooklyn Entomological Society 14: 129-141. COUNTY/tl_2014_us_county.zip (accessed Oliva A (1996) The genus Hydrochus Leach May 2016). (Coleoptera: Hydrophiloidea: Hydrochidae) United States Army Corp of Topographical in South America, with special reference to Engineers, Stansbury H, Baird SF, Girard Argentina. Bull. Ann. Soc. R. Beige Ent. 132: C, Haldeman SS, Torrey J, Hall J, Gale LD 301-341. (1852) Exploration and survey of the valley Oliva A (2000) Hydrochus synonymies. Latissimus of the Great Salt Lake of Utah: including a 12: 14. reconnaissance of a new route through the Short AEZ, Hebauer F (2006) World Catalogue Rocky Mountains. Philadelphia: Lippincott, of Hydrophiloidea-additions and corrections, Grambo & Co. 1(1999-2005) (Coleoptera). Koleopterologische Watts CHS (1999) Revision of Australian Rundschau 76: 315-359. Hydrochus (Coleoptera: Hydrochidae). Records Smetana A (1988) Review of the family of the South Australian Museum 32: 1-43. Hydrophilidae of Canada and Alaska White CE, Young FN, Downie NM (1985) A (Coleoptera). Memoirs of the Entomological checklist of the aquatic Coleoptera of Indiana. Society of Canada, No. 142. 316 pp. Indiana Academy of Science 94: 357-369. Steiner WE, Staines CL, McCann JM, Hellman JL Young FN (1954) The water beetles of (2003) The Seth Forest Water Scavenger Florida. University of Florida Studies Beetle, a new species of Hydrochus in Biology, Science Series 5: ix + 238 (Coleoptera: Hydrophiloidea: Hydrochidae) from the Chesapeake-Delmarva region. The Coleopterists Bulletin 57: 433-443. Testa S, Lago PK (1994) The Aquatic Hydrophilidae (Coleoptera) of Mississippi. Mississippi Agricultural and Forestry Experimental Station Technical Bulletin 193. 73 pp. worthington et al. 201

Figure 2. Hydrochus callosus LeConte male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 3. Hydrochus callosus LeConte distribution by county in Mississippi. 202 hydrochidae of Mississippi

Figure 4. Hydrochus excavatus LeConte male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 5. Hydrochus excavatus LeConte distribution by county in Mississippi. worthington et al. 203

Figure 6. Hydrochus inaequalis LeConte male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 7. Hydrochus inaequalis LeConte distribution by county in Mississippi. 204 hydrochidae of Mississippi

Figure 8. Hydrochus neosquamifer Smetana male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 9. Hydrochus neosquamifer Smetana distribution by county in Mississippi. worthington et al. 205

Figure 10. Hydrochus rufipes Melsheimer male genitalia. Left, ventral aspect; right, lateral aspect. Illustration modified from Hellman (1975).

Figure 11. Hydrochus rufipes Melsheimer distribution by county in Mississippi. 206 hydrochidae of Mississippi

Figure 12. Hydrochus rugosus Mulsant male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 13. Hydrochus rugosus Mulsant distribution by county in Mississippi. worthington et al. 207

Figure 14. Hydrochus simplex LeConte male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 15. Hydrochus simplex LeConte distribution by county in Mississippi. 208 hydrochidae of Mississippi

Figure 16. Hydrochus jaechi Makhan male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 17. Hydrochus jaechi Makhan distribution by county in Mississippi. worthington et al. 209

Figure 18. Hydrochus falsus Hellman, n. sp., dorsal habitus of holotype male. 210 hydrochidae of Mississippi

Figure 19. Hydrochus falsus Hellman, n.sp., male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 20. Hydrochus falsus Hellman, n.sp., distribution by county in Mississippi. worthington et al. 211

Figure 21. Hydrochus jiawanae Makhan male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 22. Hydrochus jiawanae Makhan distribution by county in Mississippi. 212 hydrochidae of Mississippi

Figure 23. Hydrochus pajnii Makhan male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 24. Hydrochus pajnii Makhan distribution by county in Mississippi. worthington et al. 213

Figure 25. Hydrochus schereri Makhan male genitalia. Left, ventral aspect; right, lateral aspect. Illustration from Hellman (1975).

Figure 26. Hydrochus schereri Makhan distribution by county in Mississippi.