11 June 1991 PROC. ENTOMOL. SOC. WASH. 93(2), 1991, pp. 248-261 THE FLOWER FLY GENUS ORNIDIA (DIPTERA: SYRPHIDAE) F. CHRISTIAN THOMPSON Systematic Entomology Laboratory, ARS, USDA, NHB-168, Smithsonian Institution, Washington, D.C. 20560. Abstract. — The flower fly genus Ornidia (Diptera: Syrphidae) is revised. The genus is redescribed; a key to species is presented; the phylogenetic relationships of the genus and species are hypothesized; the included species are redescribed; with a new species, white- headi, described from Panama (type) and Colombia; and the critical characters are illus- trated. Key Words: key, phylogenetic relationships, neotropical Ornidia is small group of brilliant metal- straight below median tubercle, with dis- lic green or purple flies found mainly in the tinct median tubercle and smaller lateral tu- New World tropics: Anyone who has spent bercle; frontal prominence distinct, low, time in these tropics knows these beautiful above middle of head; frontal triangle short, flies as they are common around human Vi as long as eye contiguity, slightly puffed habitations. The genus contains only 4 spe- out; front of female narrow, about twice as cies: One common species found every- long as wide at antennal base, as long as where in the New World tropics and that face, with convergent sides dorsally, puffed has spread extensively through the Old out, with a transverse depression about xh World tropics during the last century with of frontal length above antenna, with short commerce, two others which are less com- sublateral longitudinal depression extend- mon but widespread, and one new species, ing about xh the length of front above trans- presently known from a few specimens from verse depression. Eye pilose, holoptic in Panama and Colombia. This paper presents male. Antenna short, shorter than face; ba- a revision of the genus, with complete syn- soflagellomere elongate, twice as long as onymies (except only major references giv- broad at base; arista plumose, as long as en for obesa), descriptions, and distribu- antenna. tional and biological data for all taxa. Thorax: about as long as broad; noto- pleuron enlarged, swollen and elongate pos- Genus Ornidia Lepeletier and Serville teriorly on lateral Vi; meso-anepisternum Ornidia Lepeletier & Serville, 1828: 786. with anterior portion bare; meso-katepister- Type-species, Syrphus obesus Fabricius num with posterior % completely pilose; (orig. des.). Curran 1930: 2 (key); Val 1972 meso-anepimeron with posterior portion (key, biometry, evolution); Thompson pilose; meropleuron with barrette pilose; 1972: 106 (descr., relationships). with a patch of pile anterobasal to meta- Volucella, subg. Ornidia: Hull 1949: 348 thoracic spiracle; scutellum with a pre-api- (description); Hardy 1964: 403 (descrip- cal depression, without ventral pile fringe. tion). Wing: without microtrichia; marginal cell Head: face concave beneath antenna, closed, petiolate, with apical portion an- VOLUME 93, NUMBER 2 249 gulate posteriorly; apical crossvein reces- 5) Meso-anepimeron bare posteriorly (0) sive. or pilose (1). Abdomen: suboval, convex, without bris- 6) Meso-katepimeron (barrette) bare (0) tles. or pilose (1). Ornidia belongs to the tribe Volucellini 7) Postalar wall bare (0) or pilose poste- and is the sister of Copestylum [Volucellini riorly (1). = Graptomyza + (Volucella + (Ornidia + 8) Scutellum without (0) or with pre-api- Copestylum)), see Thompson and White- cal depression (1). head (1986) for explanation of cladistic for- 9) Medius with apical portion (apical mulae] (Thompson 1972). The genus is de- crossvein) processive (0), arcuate and fined (synapomorphy) by its facial and strongly recurrent (1) or straight (2). notopleural structure, the arrangement of a - 10) Cell R4+5 (apical cell) open (0), pet- large medial and smaller sublateral tuber- iolate (1) or bulbous apically (2). Within cles on the face (Figs. 1-3), and the enlarged, Copestylum, the apical cell varies from posteriorly produced notopleuron (Fig. 4), widely open, to petiolate and bulbous. I ac- states which are unique among flower flies. cept the widely open state as the ground plan The cladistic relationships are derived from condition for Copestylum. the following characters (see Table 1), with 11) M2 present (0) or absent (1). the polarity determined by outgroup com- 12) Larvae saprophagous (0) or special- parison (tribe Rhinigiini, genus Ferdinan- ized inquilines in nests of social Hymenop- dea): tera (1). 1) Male eyes holoptic (0) or dichoptic (1). The taxa examined were: This character varies within the genus Co- Copestylum (apicalis Loew, compactus pestylum, one species group has dichoptic Curran,ybr»ax Townsend, gibber a Schiner, eyes, the rest holoptic, which is accepted as hirtipes Macquart, marginatum Say, mexi- canum Macquart, trituberculatum Thomp- the ground plan condition. son, tympanitis Fabricius); 2) Arista bare (0), sparsely and short pi- Ferdinandea (cupreus Scopoli); lose (1), or plumose (densely and long pi- Graptomyza (alabeta Mutin, doddi Fer- lose) (2). The aristal pilosity varies greatly guson, flavicollis Ferguson, inclusa Walker, in both Graptomyza and Copestylum. In liberia Greene, longirostris Wiedemann, Graptomyza most species have the arista maculipennis de Meijere, microdon Osten sparsely pilose with short hairs, which I ac- Sacken, nigripes Brunetti, plumifer Fergu- cept as the ground plan condition (as inclu- son, signata Walker); sa), some species have only a few very short Ornidia (all species); aristal hairs, one undescribed species from Volucella (bombylans Linnaeus, decolo- Australia has no aristal hairs, and some spe- rata Walker, elegans Loew, inanis Linnae- cies have long and numerous hairs (as in us, inflata ¥&bricms,jeddona Bigot, linearis longirostris). In Copestylum, there are a few Walker, nigricans Coquillett, pellucens Lin- species groups with distinctive aristal pi- naeus, rotundata Edwards, tabanoides Mot- losity, but these are all clearly derived from schulsky, trifasciata Wiedemann, and zo- the basic plumose condition. One species, naria Poda). pseudotachina, has the arista bare, a sec- I now accept the diphyletic origin of the ondary reduction. Old World volucellines as Graptomyza are 3) Meso-anepisternum bare (0) or pilose now known to be saprophagous, not spe- (1). cialized inquilines. Also, Tachinosyrphus is 4) Meso-katepisternum continuously pi- no longer accepted as a genus distinct from lose (0) or bare medially (1). Copestylum (new synonymy) as that ar- 250 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON head I)Y£ rnesonotum 2nd sternum Figs. 1-8. Features of Ornidia. 1, 2. Facial profiles. 1, aemula Williston. 2, major Qurran. 3. obesa Fabricim, head, lateral. 4. obesa Fabricius, notopleuron and adjacent structures, dorsal view. 5, 6. Wing, apical half. 5, aemula Williston. 6, major Curran. 7,8. Abdominal sternum, lateral profile. 7, major Curran. 8, aemula Williston. rangement left Copestylum as undefined. acter, the pilosity of the posterior portion The above cladistic formula, which is the of the anepimeron. In my previous analysis, same as my 1972 phylogeny, is derived when I considered the pilose condition to be prim- the type species are used as exemplars (CI itive in all situations. Hence, Copestylum = 87, RI = 71, 1 tree). The possibility that was defined by a bare posterior anepimeron. Ornidia is a specialized subgroup of Cope- However, under a strict outgroup criterion, stylum rests on the evaluation of one char- the bare condition is primitive within the VOLUME 93, NUMBER 2 251 Table 1. Characters of volucelline taxa. Characters Taxa l 2 3 4 5 6 7 8 9 10 li 12 Ferdinandea cuprea 0 0 0 0 0 0 0 0 0 0 0 0 Graptomyza inclusa 1 1 1 1 0 0 0 1 2 0 0 0 Graptomyza longiventris 1 2 1 0 0 0 0 1 2 0 0 0 Volucella pellucens 0 2 1 0 0 1 0 1 1 Ornidia obesa 0 2 0 0 1 1 1 2 0 Copestylum marginatum 0 2 0 0 0 1 0 2 0 Copestylum mexicanum 0 2 0 0 0 0 0 1 0 Copestylum nasicum 1 2 0 0 0 0 0 1 0 Copestylum tympanitis 0 2 0 0 0 0 1 1 0 Copestylum apicale 0 2 0 0 0 0 1 0 0 Copestylum pseudotachina 0 2 0 0 0 1 0 1 0 Copestylum trituberculatum 0 2 0 0 0 0 0 0 0 Copestylum fornax 0 1 0 0 0 0 0 2 0 Copestylum hirtipes 0 2 0 0 0 0 0 0 0 Copestylum gibbera 0 2 0 0 0 0 0 1 0 Copestylum compactus 0 2 0 0 0 0 0 2 0 Copestylum ground plan 0 2 0 0 0 1 0 0 0 See text for descriptions of the characters. tribe Volucellini. Copestylum is a large ge- ciput extensively white pollinose nus (350+ species) with many distinct aemula Williston - Apical wing spot small (Fig. 6); 2nd sternum groups. When exemplars of these groups are without process (Fig. 7) 2 added to the analysis and strict outgroup 2. Mesonotum and 3rd tergum extensively pale criterion is used, a far different statement pilose; occiput shiny. Scutellar depression di- of relationship results (Volucellini = Grap- vided medially whiteheadi Thompson tomyza + (Volucella + Ornidia + Cope- - Mesonotum and 3rd tergum black pilose; oc- ciput extensively white pollinose 3 stylum), consensus of some 100 trees). Thus, 3. Scutellar depression divided medially; with until Copestylum can be revised, the rela- prescutellar bristles major Curran tionships of Ornidia will remain uncertain. - Scutellar depression continuous medially; Ornidia is an endemic New World group without prescutellar bristles obesa Fabricius consisting of 4 known species. One species (obesa), however, is hemisynanthropic and Ornidia aemula Williston has spread extensively in the Pacific and Figs. 1, 5, 8,9,13 across the Orient to the east coast of Africa. Volucella aemula Williston 1888:272. Type- The cladistic relationships among the spe- locality: Bolivia, Santa Cruz, Piedra Blan- cies (Ornidia = aemula + (obesa + (major ca [4 km west of Corumba, Mato Grosso, + whiteheadi)))are tentative as they rest on Brazil].