18 August 1994 PROC. ENTOMOL. SOC. WASH. 96(3), 1994, pp. 483-495 REVISION OF THE STERPHUS CYBELE SPECIES GROUP (DIPTERA: SYRPHIDAE) HEIKKJ HIPPA AND F. CHRISTIAN THOMPSON (HH) Department of Entomology, Swedish Museum of Natural History, Stockholm, Sweden; (FCT) Systematic Entomology Laboratory, ARS, USDA, NHB-168, Smithsonian Institution, Washington, DC. 20560, U.S.A. Abstract.? The Sterphus cybele species group is revised and four new species are de- scribed: janzeni Thompson (Costa Rica & Panama); calypso Hippa (Bolivia); cydippe Hippa (Columbia); and venezuelaensis Thompson (Venezuela). The phylogenetic rela- tionships among these are venezuelaensis + ((cybele + janzeni) + (calypso + cydippe)). A new key to the species of Sterphus is given. Key Words: Neotropics, key Flower flies of the genus Sterphus are found throughout the New World tropics. They breed in dead wood, aiding in the nu- trient recycling, and are pollinators. Due to their diverse life cycle, the group is a good indicator of the health of tropical forests. The relationships among a group of species of Sterphus are here documented and four species previously unknown to science are described. This information, along with the included identification key, will be useful to scientists studying flies, and to action agen- cy personnel charged with identifying flies. Sterphus Philippi was revised by Thomp- son (1973). At that time, he was uncertain as to the placement of the species 5. cybele Hull as that species was known from only two females. Hippa (1978) revised the tribe Xylotini, intrageneric classification of Ster- phus, and described 8 new species of Ster- phus. Since our work, males of new species closely related to S. cybele have been dis- covered. The characters of these species confirm our placement of S. cybele in Ster- phus. Sterphus cybele and related species are here revised. A new key to all species of Sterphus is given. The classification of Ster- phus used here is that of the senior author (Hippa 1978). This usage should not be con- strued as a change in view of the junior author (Thompson 1973). Sterphus cybele species group Description.?Head: Face tricarinate, practically straight in profile; basoflagello- mere elongate, not more than twice as long as broad, with lateral sensory pit on mesial surface sexually dimorphic, being more dor- soapical and circular in female and more basoventral and elongate in male; male hol- optic; frontal triangle bare except rarely with a few marginal hairs, shiny anteriorly, pol- linose posteriorly; front with broad polli- nose fascia divided into differently reflec- tive areas. Thorax: Mesonotum dull due to both shagreening and pollinosity, with pollinose pattern composed of posteriorly furcate me- dial vitta and postsutural submedial vittae, without pollinose transverse sutural fasciae, with long appressed pale pile laterally; with- out strong spinose hairs above wing base; metasternum well developed, pilose; scu- tellum with apical marginal sulcus, without 484 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON strong marginal hairs or bristles, with well- developed subscutellar fringe. Legs: Hind trochanter simple or at most with small tu- bercle, without a distinct spur; hind femur moderately thickened, ventrally with ante- rior and posterior rows of spinose hairs, in male with a basal patch of black setulae; hind tibia with well-developed basoventral median carina although apical end not strongly raised, with erect ventral hairs, with both apicoventral corners produced, with apical patch of pale pile on posterior sur- face; front and middle tibiae yellow. Wing: Slightly to moderately darkened, without conspicuous color pattern; without stig- matic crossveins. Abdomen: Parallel-sided, dark, with shiny areas laterally and dull areas medially on each tergum, without conspicuous pilose pattern. Geographic distribution.?Species of the S. cybele group are found only in the Neo- tropical Region, and range from Costa Rica to Peru. Phylogenetic relationships.?The S. cy- bele species group is distinguished within Sterphus by the pilose metasternum (aut- apomorphy). The group has retained the following plesiomorphic character states (the corresponding apomorphic states are in pa- rentheses) of Sterphus as a whole (ground- plan; Macrometopia, the probable sister to Sterphus (Thompson 1975), used as an out- group): 1) pollinose, pale face (largely dark and shiny face with only oblique lateral pol- linose vittae overlying the paler integument color); 2) short basoflagellomere (elongate basoflagellomere); 3) simple base for tho- racic pile (tuberculate base for pile); 4) hind trochanter spur absent (developed); 5) un- modified abdomen (petiolate abdomen); and 6) unmodified hind femur (incrassate hind femur). The group has the following im- portant apomorphic character states (re- spective plesiomorphic states in parenthe- ses): 7) strongly developed metasternum (weakly developed metasternum); 8) both retro- and prolateral apicoventral spur on hind tibia (only retrolateral spur); 9) pilose metasternum (bare metasternum); and 10) long pro- and retrolateral spine rows on hind femur (hind femur only with subapical spine rows). Of these character states, 9 defines the group. Other apparent synapomorphies are 11) the sexually dimorphic antenna in which the sensory pit on the inner lateral side of the basoflagellomere is slit-like in the male and normal (oval) in the female and 12) the male hind femur with a subbasal prolateral patch of black setulae. The im- portance of the last character (12) is uncer- tain as males are not known for many spe- cies of Sterphus. Characters 2, 3, and 6 exclude the deri- vation of the S. cybele group from within Sterphus (Crepidomyia); 2, 5 and 6 from Sterphus (Tatuomyia); and 6 from Sterphus (Telus). Characters 7 and 8 may demon- strate the common origin of the S. cybele group with Crepidomyia, Tatuomyia and Telus, and exclude it from belonging within Sterphus {Sterphus). Hence, we suspect the S. cybele group to be an early derivative of the clade leading to Crepidomyia, Tatu- omyia and Telus. As there is still consid- erable uncertainty regarding the monophyly of the Sterphus complex (Hippa 1978), the final status of the cybele group cannot be resolved here. The relationships and cladogenesis in the S. cybele group are easily traced (Fig. 26). The probable outgroup for S. cybele group is the S. chloropygus group (see Thompson 1973). S. venezuelaensis derived first: it re- tained a dark face with oblique pollinose stripes, the short basoflagellomere, the hind trochanteral spur and largely dark front and middle femora. S. cybele and S. janzeni are the second derivatives; they developed an almost completely yellow and almost com- pletely pollinose face, elongate oval baso- flagellomere 3, lost the hind trochanteral spur and developed the totally pale anterior and middle femora. S. calypso and S. cy- VOLUME 96, NUMBER 3 485 dippe are the last derivatives; they further developed a totally yellow and pollinose face and elongate rectangular basoflagellomere. Sterphus calypso Hippa, NEW SPECIES Diagnosis.?A moderately slender spe- cies with pale face, yellow gena and yellow anterior and middle legs. Description.?Male: Length 16 mm, wing length 14 mm. Differs from the description of S. cydippe as follows: Gena anteriorly to the level of facial grooves shining yellowish orange; ba- soflagellomere missing; frontal triangle with distinct hair rows along eye margins; post- ocellar orbits only dorsolaterally with few tiny black bristles; scutellum on disc pale pilose but mixed with few longer black hairs; a short narrow bare stripe at base of 2nd basal cell; halter orange; front and middle trochanter yellow, hind trochanter pale brown; hind femur and tibia structure (Fig. 1); hind femur except about basal fifth and actual apex brown, the shifting from yellow to brown very gradual; hind tibia basally with only a few pale hairs; hind tarsus with 3 basal segments brownish; abdomen (Figs. 21, 25); all sterna dark to blackish brown except sternum 2 on apical half and sternum 3 on basal half obscurely paler brown; pos- terior part of sternum 4 with black hairs; genitalia (Figs. 10, 19). Female: Length 17 mm, wing length 15 mm. Like male except for usual sexual dimor- phism and: antenna (Fig. 12) with basofla- gellomere brown, arista paler brown; frons with a broad brownish pollinose transverse band and ? coinciding band of short pale and few mixed dark hairs; dorsal part of postocellar orbits with mixed pale and black hairs; pale thoracic hairs golden yellow; wing orange gray; bare stripe on 2nd basal cell very small and inconspicuous; front and middle coxae yellowish, hind coxa yellow- ish brown, ventrally brown; hind trochanter orange brown, hind femur orange brown but apical third especially dorsally darker; basal third of hind tibia pale yellowish brown, mostly pale haired; hind tarsus wholly yel- low; abdomen (Fig. 25) with shining areas of terga 2 and 3 with strong violet reflec- tions, with very obscure paler underlying coloration; the pale lateral hairs on terga 2 and 3 partly depressed, appearing as pale oblique spots to naked eye; tergum 5 dark, shining, black pilose except yellow pilose anterolaterally; posterior margin of sternum 1, sternum 2 and sternum 3 except the pos- terior margin brown; basal two thirds of sternum 5 shining black, apical part brown and paler pollinose, hairs black except ba- solaterally pale. Holotype ^ ?S a 2,3,4 Fig. 26. Phylogeny of the Sterphus cybele species group. Characters with states (plesiomorphic to apomorphic; white = plesiomorphic, black = apomorphic, and gray = intermediate state in a morphocline; arrows show direction of character state transition; numbers at the nodes indicate the characters that define the clades): 1, metasternum bare ??pilose; 2, face dark ?? orange; 3, face partially shiny ?? entirely pollinose; 4, basoflagellomere short ?* elongate oval ?* elongate rectangular; 5, fore and mid femora extensively dark ?* extensively pale. pale pollinose, pale pilose except dorsally mixed with stronger black bristles. Thorax: Mesonotum black, grayish brown pollinose, with a longitudinal me- dian posteriorly bifurcate paler grayish pol- linose stripe extending from anterior mar- gin to about posterior fourth and with more indistinct postsutural midlateral pale pol- linose stripes; hairs at anterior margin, me- dially on anterior half and laterally yellow- ish white, otherwise black. Scutellum blackish, semishining, pale grayish haired (hairs worn off disk) except with few long dark hairs at margin; subscutellar fringe grayish. Pleurae, including metasternum, blackish with partly paler sutures, slightly pale pollinose, yellowish white pilose; spira- cles pale brown. Wing slightly smoky, stig- ma pale brown; microtrichose except nar- rowly bare posteriorly along the basal half VOLUME 96, NUMBER 3 491 of vein 1 A. Calypter whitish, with slightly darker border and fringe. Halter yellowish white. Coxae blackish brown to black, tro- chanter brown, hind trochanter with a slight indication of a tubercle, all pale haired. Hind femur and tibia (Fig. 4). All femora, front and middle tibiae and tarsi yellow to orange yellow, hind tibia brown with slightly paler basal part and apex, hind tarsus yellow ex- cept metatarsus darker brownish, hairs of all yellowish except a dorsal retrolateral stripe on apical 2h and broad apicodorsal part of hind femur and whole of hind tibia except the prolateral basal third and a small- er prolateral and larger retrolateral apical patch with black hair. Abdomen (Fig. 22): Tergum 1 shining black except an anterior median dull black- ish brown patch, terga 2 and 3 dull blackish brown with paler brown shining lateral patches, tergum 4 shining brown with a me- dian Y-shaped dull patch (the shining-dull pattern marked with broken lines in Fig. 22); hairs on tergum 1, at anterior margin of tergum 2, on shining areas of terga 2-4, except the posterior part of tergum 4, pale, otherwise black. Sternum 1 shining blackish brown except laterally gray pollinose, ster- num 2 shining pale brown, sternum 3 shin- ing with anterior third pale brown, posterior two thirds dark brown, sternum 4 shining except slight posterolateral pollinosity, brown, all with pale hairs. Genitalia (Figs. 7, 17). Female: Unknown. Holotype 8.-COLOMBIA, West. Cord., Monte Socorro, 3800 m, Coll. Fassl, de- posited in the British Museum (Natural History), London. Discussion.?For discussion, see under S. calypso. Sterphus janzeni Thompson, NEW SPECIES Diagnosis.?A moderately slender spe- cies with dorsomedially darkened pale face, black gena, yellow front and middle legs, and black pilose hind tarsus. Description.?Male: Length 14 mm, wing, 12 mm. Head: Face yellow except narrowly dark brown dorsally, with pale pollen; gena blackish, shiny anteriorly, with sparse pale pollen and pile posteriorly; frontal lunule brown; frontal triangle blackish brown, an- terior Vi shiny, posterior % grayish polli- nose, with only a few pale hairs along eye margins; vertical triangle black, anteriorly densely pollinose, dark brown pilose; occi- put black, with dense pale pollen ventrally but becoming sparser dorsally, with pale pile except with a few intermixed black hairs dorsally; antenna dark brown except pale brown basoventrally on basoflagellomere, with basoflagellomere about l'/s times as long as wide; antenna same shape as female, but with sensory pit more elongate and ba- soventral as in cydippe (Fig. 11); arista pale brown, apically darker. Thorax: Mesonotum black, with brown pollen, with a narrow medial pollinose vitta pale gray and extending from anterior mar- gin to posterior Vi, with postsutural sub- medial vittae indistinct and pale brownish, generally with black pile, with yellow pile narrowly on anterior margin and medial vit- ta, with long appressed yellow pile laterally; scutellum black, shiny, with erect yellow pile with a few longer dark hairs, with subscu- tellar fringe grayish yellow; pleura dark brown to black, with sutures paler, with sparse pale pollen, with pile yellow to yel- lowish white; anterior spiracular fringe brown; posterior spiracular fringe pale brown; metasternum black, with yellow pile; calypter whitish with darker yellow to brownish margin and fringe; halter orange to yellow. Legs: Front and middle coxae brown to black, gray pollinose, pale pilose; front and middle trochanters brown, with pale pile; hind coxa black, with pale pile; hind trochanter blackish brown, apically paler, with pale pile; front and middle fem- ora, tibiae and tarsis yellow, with pale pile; hind femur as in cydippe (Fig. 4) reddish brown, with pale pile except for dark pile 492 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON on apex and apicodorsal lh, with ventral spi- nose pile black; hind tibia dark blackish brown, with dark pile except for pale pile apicoposterolaterally; hind tarsus blackish brown, with dark pile. Wing: Slightly gray- ish brown, with stigma pale brown, micro- trichose except bare as follows: anterobasal Vi of 2nd basal cell, posterobasal V2 of anal cell. Abdomen (Fig. 20): 1st tergum shiny black, with anteromedial areas dull; 2nd through 4th tergum dull black brown on medial pollinose areas, with lateral shiny areas on 2nd and 3rd terga dark brownish orange and on 4th tergum brownish black; genitalic segments black, shiny, black pi- lose; dorsal pile dark and depressed on dull areas, pale and erect on shiny areas; 1 st, 3rd and 4th sterna dark brown, shiny except dull pollinose on laterally on 1 st and apically on 3rd and 4th, with pale pile except for a few intermixed dark hairs on 4th; 2nd sternum pale brown, shiny, with pale pile. Female: Like male except for usual sexual dimorphism and: face yellow, with dorso- medial brown area triangular; front shiny black except for broad transverse pollinose fascia, with fascia gray anteriorly and brownish posteriorly, with pale pile ante- riorly becoming gradually darker posteri- orly; vertex shiny black, with dark pile; hind femur (Fig. 5); abdomen with lateral shiny areas slightly steel blue. Holotype 6.-COSTA RICA, Puntarenas Prov., Monteverde, 1400 m, 30 IV 1989, P. Hanson, Malaise Trap, deposited in In- stituto Nacional de Biodiversidad, San Jose. Paratypes.-COSTA RICA, Cariblanco, 25 March 1916, Janson (1 9, BMNH); San Jose Prov., P. N. Braulio Carrillo, 9 km NE Tunnel, 1100 m, 15 IV 1989, P. Hanson (1 9 UCR); Guanacaste Prov., Estac. Pitilla, 9 km south Santa Cecillia, UTM 330200 380200, May 1989, GNP Biodiversity Sur- vey, INBIOCRI000008935 (1 $, INBIO); Guancaste Prov., Lado suroeste del Volcan Cacao, Est. Cacao, 1000-1400 m, LN 323300 375700, June 1990, II Curso Para- taxon. INBIOCRI0000248098, INBIO- CRI000247969 (2 9, INBIO, USNM), 21- 29 May 1992, M. A. Zumbado INBIOCRI- 000410973 (1 6, INBIO); Guancaste Prov., Derrumbe, Est. Cacao, lado oeste del Vol- can Cacao, 1400 m, LN 323700 376700, 21-29 May 1992, III Curso Parataxonom. INBIOCRI000409775-409778 (4 6, IN- BIO); San Jose Prov., Zurqui de Moravia, 1600 m, IV 1991, P. Hanson (1 9, UCR); San Jose Prov., San Gerado de Dota, near Finca Zacatles, 26 Feb 92, F. C. Thompson (1 6, 1 9 USNM); Puntarenass Prov., Coto Brus, Est. Biol. Las Alturas, 1500 m, LS 3222500 591300, Ene 1992, M. Zumbado INBIOCRI000401865 (1 <5, INBIO); Pun- tarenas Prov., Golfo Dulce, 3 km SW Rin- con, 10m, III 1991, P. Hanson (1 9, USNM); PANAMA, Chiriqui Province, 2 km west of Cerro Punta, 1700 m, 19 May to 8 June 1977, Peck and Howden (1 9, CNC). Discussion.?S. janzeni is closely similar to S. cybele, but the two species can be dis- tinguished by the following characters: in S. cybele the wings are distinctly orange brown with a rather sharply contrasting long paler area in the marginal cell at fork of R2 + 3- R4 + 5 and the 2nd basal cell is wholly microtrichose, in S. janzeni the wings are only slightly darkened grayish brown, with smaller and inconspicuous paler area in marginal cell and the basal anterior half of the 2nd basal cell with the microtrichia re- duced; the hind femur is less darkened in S. janzeni than in S. cybele; the hind tarsus is blackish brown and black haired in S. janzeni, hind metatarsus pale brown, other hind tarsal segments yellowish, all with pale hairs in S. cybele; the shining markings on terga are more metallic, with brassy and purple reflections and without traces of pal- er underlying coloration in S. cybele, less metallic, with slight steel blue reflections and especially those on terga 2 and 3 with the integument at them distinctly paler; ster- num 2 is pale brown in S. janzeni, black in 51. cybele, all sterna are also more metallic in latter; sterna 3-4 are medially largely dark haired in S. cybele, a few distinct dark hairs only apicomedially on sternum 4 in S. jan- VOLUME 96, NUMBER 3 493 zeni. S. cybele is also slightly more robust than 51. janzeni. This beautiful species is dedicated to Dr. Daniel H. Janzen in recognition of all he has done to insure the survival of this spe- cies and a vast number of other Central American taxa. Sterphus venezuelaensis Thompson, NEW SPECIES Diagnosis.?A dark robust species with medially dark face, dark anterior and mid- dle femora and conspicuous metallic ab- dominal spots. Description.?Male: Length 17 mm, wing length 15 mm. Head: Face blackish brown on median carina but gradually fading to pale yellowish white laterally, medially shining, laterally with oblique pale pollinose bands; gena black, anteriorly shiny and bare, posteriorly faintly pale pollinose, pale pilose. Antenna (Fig. 15): all segments blackish brown, arista on basal half brown on apical half blackish brown. Frontal lunule blackish brown, fron- tal triangle black, anterior half shiny, pos- terior half gray pollinose and with a row of pale hairs along eye margin. Vertical tri- angle black, apically heavily and behind posterior ocelli very faintly pale pollinose, blackish brown pilose. Postocellar orbits black, dorsally very slightly paler pollinose and mainly with dark hairs, otherwise heavily pale pollinose and with pale hairs. Thorax: Mesonotum black, brown pol- linose, with paler grayish posteriorly furcate median vitta extending from anterior mar- gin to about posterior fourth, and with post- sutural sublateral longitudinal stripes with more reddish brown pollinosity when seen from behind; anteriorly with mixed yellow and black hairs, posteriorly black haired, the long lateral hairs yellowish, golden. Scu- tellum black, practically nonpollinose, more shiny than mesonotum, golden yellowish haired except mixed with a few long black hairs especially toward margins, subscutel- lar fringe yellowish. Pleurae, including metasternum, black with partly paler brownish sutures, faintly pale pollinose ex- cept more heavily on posterior part of meso- and dorsal part of katepisternum, the hairs golden yellow; spiracles brown. Wing pale grayish brown, stigma pale orange brown; microtrichose except bare posteriorly along vein 1 A. Calypter whitish with darker yel- lowish brown border and fringe on upper and brownish border and fringe on lower lobe. Halter orange. Coxae blackish, tro- chanters brown to blackish, hind trochanter with a distinct tubercle, all pale yellowish haired. For hind femur and tibia, see Fig. 3. Femora blackish, partly metallic except front and middle femora becoming through brown yellowish at about apical fourth, more widely prolaterally and ventrally than retro- laterally and dorsally, and about apical fourth of hind femur brownish; front and middle tibiae and tarsi orange yellow; hind legs dark brown except tibia slightly paler at basal third; hairs pale yellowish except partly apically and ventrally on anterior and middle femur, on apical fourth of hind fe- mur, on hind tibia except a distinct trian- gular apical retrolateral patch, and on hind tarsus dark. Abdomen (Fig. 23): Tergum 1 mostly shining steel-blue, terga 2 and 3 dull black- ish brown with conspicuous shining steel colored lateral patches at which the integ- ument appears slightly paler brown, tergum 4 shining brown, basolaterally metallic, with a median Y-shaped dull blackish brown patch (the shining/dull pattern of terga is marked with broken lines in Fig. 23); hairs on terga black except on tergum 1, at an- terior margin and on shining areas of terga 2 and 3 and anteriorly and laterally on ter- gum 4 pale, those on terga 3 and 4 partly depressed appearing as oblique pale patches by naked eye. Sternum 1 black, laterally pale pollinose, sternum 2 and % of sternum 3 pale brown, the rest brown, all with long pale hairs except with a few mixed dark ones on apical part of sternum 4. Genitalia (Figs. 8, 15). Female: Unknown. Holotype 8.-VENEZUELA, Rancho 494 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON Grande, nr. Maracay, 26.IV. 1946, depos- ited in the American Museum of Natural History, New York. Paratype, Venezuela, 1857, Alte Sammlung (1 S, NMW). Discussion.?S. venezuelaensis is easily distinguished from the other species of the S. cybele group by the following characters: Face medially dark and with oblique lateral pollinose vittae, not uniformly yellow and pollinose; front and middle femora mostly dark, not yellow; hind trochanter with a dis- tinct tubercle, not only with an indication of such; characteristic shape of hind femur (Figs. 1-6); more strongly metallic abdom- inal maculae and very different genitalia. KEY TO THE SPECIES OF STERPHUS PHILIPPI 1. Abdomen petiolate, minimal width usually less than % maximal width 2 - Abdomen not petiolate, if slightly constricted, then minimal width never less than % max- imal 7 2. Hind tibia with apical spur 5 - Hind tibia without apical spur 3 3. Hind leg orange except brownish coxa and apical 2 tarsomeres, face straight (Brazil) .. tinclus (Fluke) - Hind leg bicolored; hind coxa, trochanter, fe- mur and apical tarsomeres black; hind tibia and basitarsomere orange; face with tuber- culate swelling below 4 4. Tibia unicolorous orange; wing entirely mi- crotrichose (Venezuela) .... incertus Thompson - Tibiae bicolorous, orange brown basally and dark brown apically; microtrichose except bare in front of anal vein (Colombia) nitidicollis Hippa 5. Hind tibia with 2 apical spurs; abdominal pet- iole long, about % as long as second segment 6 - Hind tibia with 1 apical spur; abdominal pet- iole short, about 'A as long as second segment (Panama to Brazil) .... coarctatus (Wiedemann) 6. Anal cell bare except microtrichose apical '/t; middle leg orange (Brazil) .... fulvus Thompson - Anal cell almost completely microtrichose; middle leg black (Brazil) batesi (Shannon) 7. Abdomen red; wing completely dark except for light apical fascia (Ecuador) .... telus Thompson - Abdomen dark; wing hyaline or almost com- pletely hyaline 8 8. Metasternum pilose 26 - Metasternum bare 9 9. Face shiny medially, pollinose laterally, most- ly black, never completely yellow or orange 14 - Face completely pollinose, orange, yellow or black in ground color 10 10. Gena and most of frons orange, all of frontal triangle of male and lower lh of frons in female orange 11 - Gena and frons black 21 11. Legs orange 13 - Legs dark 12 12. Thoracic pile reddish brown; tibial bases red- dish brown (Juan Fernandez Is.) aurifrons Shannon - Thoracic pile white and black; tibiae com- pletely black (Chile) coeruleus (Rondani) 13. Mesonotum entirely short yellow pilose; basal cells microtrichose; hind trochanter with a well developed broad spur; hind femur long pilose, with hairs longer than tibial width; 4th tergum entirely shiny (Columbia) aureus Hippa - Mesonotum short yellow pilose with longer black pile intermixed on posterior Vr, basal cells partially bare basomedially; hind tro- chanter without a spur; hind femur short pi- lose, with hairs shorter than tibial width; 4th tergum dull pollinose medially (Colombia) ... ochripes Hippa 14. Mesonotum with longitudinal vittae of golden appressed pile on posterior half 15 - Mesonotum without longitudinal vitta of golden pile 16 15. Abdomen with fasciae of golden tomentose pile on 3rd thru 4th (males) or 5th (female) terga; wing diffusely yellowish brown (Brazil) shannoni Thompson - Abdominal terga without apical golden pilose fasciae; wing with distinct diagonal brown vit- ta (Mexico to Brazil) ... plagiatus (Wiedemann) 16. Hind trochanter and tibia without spurs or process 3 - Hind trochanter and/or tibia with distinct spurs or processes 17 17. Transverse suture golden pollinose; hind tibia without apical spur (Costa Rica to Argentina) genuinus Complex - Transverse suture without golden pollinosity; hind tibia usually with long apical spur .... 18 18. Front and middle tibiae and tarsi orange (Co- lombia) fassli Hippa - Front and middle legs more extensively dark, at least with apical tarsomeres black 19 19. Mesonotum with thick, opaque silvery gold pile on anterior and lateral margins; frontal triangle of male shiny black. Hind trochanter of male with simple spur (Venezuela) woodorum Thompson - Mesonotum black and yellow pilose anteri- orly and laterally, completely black pilose VOLUME 96, NUMBER 3 495 above wing; frontal triangle of male golden pollinose 20 20. Basoflagellomere circular; mesonotum shiny on disc; hind trochanter with a simple spur; hind tibia without a long apical spur nor ap- icoventral carina (Colombia to Ecuador) ... nitidicollis Hippa - Basoflagellomere trapezoidal; mesonotum entirely dull pollinose; hind trochanter of male with a bilobed spur; hind tibia with a long apical spur and an apicoventral carina (Bo- livia) 21 21. Front and middle femora dark on basal 4/5 or more 22 - Front and middle femora dark on basal xh only, orange apically (Bolivia) ... andicus Hippa 22. Face orange 24 - Face dark, brown to black 23 23. Mesonotum with tufts of long appressed gold- en hairs above wing and on postalar callus; scutellum partly yellow pilose; front and mid- dle tibiae orange brown on basal 'h; femora extensively pale pilose (Bolivia) .. incarum Hippa - Mesonotum and scutellum entirely black pi- lose; tibiae black; femora black pilose (Ven- ezuela) chloropygus (Schiner) 24. Legs black (Bolivia) slimulans Thompson - Front and middle tibiae and tarsi orange .. 25 25. Terga 4 and 5 with pile similar to that of other terga; terga 2 and 3 more extensively shiny, with transverse metallic bluish maculae (Co- lombia) sapphirifer Hippa - Terga 4 and 5 with conspicuous thick opaque yellowish-white pile, strongly contrasting with that of other terga; terga 2 and 3 dull, shiny only narrowly laterally (Colombia) pilifer Hippa 26. Anterior 4 femora black on basal %; face shiny medially, only with oblique pollinose lateral vitta, with median carina broadly darkened through the whole length (Venezuela) venezuelaensis Thompson, n. sp. - Anterior 4 femora yellow, face entirely pol- linose, entirely pale or with a triangular dor- somedian darkened patch not reaching the upper mouth edge 27 27. Gena yellow anteriorly (Bolivia) calypso Hippa, n. sp. - Gena entirely black 28 28. Hind tarsus pale, with pale pile; 2nd basal cell microtrichose 29 - Hind tarsus dark, with dark pile; 2nd basal cell bare on basal anterior half (Costa Rica, Panama) janzeni Thompson, n. sp. 29. Sternum 4 partially black pilose; basoflagel- lomere ovate (Fig. 14) (Colombia, Peru) ... cybele (Hull) Sternum 4 entirely yellow pilose; basoflagel- lomere rectangular (Fig. 11) (Colombia) . .. cydippe Hippa, n. sp. ACKNOWLEDGMENTS We thank Adrian Pont, the Natural His- tory Museum (formerly the British Museum (Natural History)), London (BMNH); Da- vid A. Grimaldi, the American Museum of Natural History, New York (AMNH); Man- uel Zumbado, Institute Nacional de Bio- diversidad, Heredia (INBio); Ruth Lichten- berg, Naturhistorisches Museum, Vienna (NMW); J. R. Vockeroth, Canadian Na- tional Collection, Agriculture Canada, Ot- tawa (CNC); Paul Hanson, University of Costa Rica, San Jose (UCR); W. Tobias, Senkenbergische Museum, Frankfort am Main (SMF); Manuel Zumbado, Institute Nacional de Biodiversidad, San Jose (IN- Bio); for permission to study material in their care (other collection acronyms used are USNM for United States National Mu- seum (= the National Museum of Natural History, Washington and for Cornell Uni- versity, Ithaca). We also thank Drs. Neal Evenhuis, Bishop Museum, Honolulu; Bri- an Brown, Maryland Center for Systematic Entomology, College Park; Tadeusz Zat- warnicki, Agricultural College, Wroclaw; Arnold S. Menke, Douglass R. Miller and Norman Woodley, Systematic Entomology Laboratory, USDA, Washington, for their critical reviews of the manuscript. LITERATURE CITED Hippa, H. 1978. Classification of Xylotini (Diptera, Syrphidae). Acta Zoologica Fennica 156, 153 pp. Hull, F. M. 1951. Some New World Xylotinae (Dip- tera: Syrphidae). Pan-Pacific Entomologist 27: 183- 186. Thompson, F. C. 1973. Review of the genus Sterphus Philippi (Diptera: Syrphidae). Part I. Entomolo- gica Americana 46: 185-240. . 1975. Notes on the status and relationships of some genera in the tribe Milesiini (Diptera: Syr- phidae). Proceedings of the Entomological Society of Washington 77: 291-305.