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Key to the Syrphidae of the southeastern US
Key taken from Howard Vincent Weems unpublished PhD. THE SYRPHID FLIES OF SOUTHEASTERN UNITED STATES, 1953. Red entries detail species changes and movements since then. Species immediately after the genus name are species that have not changed placements since Weems' paper appeared. Parenthetic entries show number of Weems' species and the number of current Nearctica listed species (2W [Weems], 3N [Nearctica]). Page numbers refer to pages where the genus keys appear in the original Weems' paper. Figure references are being removed with revision but figures after Fig #136 in Weems were imprint photos of actual specimens and did not reproduce well in my copy. Earlier figures are being added where useful or of good quality. Some figures are from the Nearctic Diptera volume 1 key of Vockeroth and Thompson where clarifying. The list at the end is of species added to the Syrphid group after 1953 and some of these may be southeastern and would have to be added to the keys. Species occurring strictly in the NE or Great Lakes states likely are not in the Weems' listing.
This key is under testing and revision. Expected Arkansas Species List
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1. Antennae with a terminal style
M. villosus
2 1. Antennae with an arista arising dorsally on basal half of third antennal segment
2(1). Eyes pilose; third antennal segment tapering from base
C. erraticum
CALLICERA Panzer (pg. 343) (2W, 3N) Status of C. johnsoni Hunter unknown Second species probably subspecies of johnsoni
2. Eyes bare; third antennal segment variable 3
3(2). First two antennal segments short, third compressed laterally with terminal style on produced upper angle (see first image at 1) 4 3. Antennae cylindrical, first two segments elongate, third tapering and bearing a small terminal style
5
4(3). Arista slender, bristle-like (see first image at 1); large species, about 15-16 mm in length
M. villosus
MERAPIOIDUS Bigot (pg. 441) (1W, 1N) M. villosus Bigot
4. Arista stout, densely micro-pilose; small species, about 6-7 mm in length
P. pergandei
PELECOCERA Meigen (1W, 1N) P. pergandei Williston
5(3). Antennal process greatly produced, longer than first antennal segment; hypopygium often globose; metasternum membranous behind; stigmatic crossvein present but indistinct
C. abbreviata 6 5. Antennal process reduced or absent, or if present not over half length of first antennal segment (see image at 3); apex of abdomen usually pointed in both sexes; metasternum membranous behind or wholly chitin encircled
7
6(5). Abdomen thick basally, second segment but little constricted; first abdominal segment bright yellow dorso-laterally; loop of R4+5 spurred (see second image at 5); not exceptionally large species
C. abbreviata
TENTHREDOMYIA Shannon (Now CERIANA) (pg. 445) (2W, 0N) T. abbreviata (Loew) moved to CERIANA T. mime (Hull) moved to CERIANA
6. Second abdominal segment petiolate, elongate, expanded distally; first abdominal segment dark dorso-laterally; seldom spurred; exceptionally large species, 16-18 mm. in length, excluding antennae
M. floridensis
MONOCEROMYIA Shannon (pg. 449) (1W, 1N) Now M. floridensis (Shannon)
7(5). Metasternum membranous posteriorly; abdomen constricted sub-basally, but second segment not distinctly long and slender
CERIOIDES Rondani (Now SPIXIMORPHA) (pg. 443) (1W, 0N) C. signifera (Loew) now in SPHIXIMORPHA
7. Metasternum completely sclerotized; second abdominal segment distinctly slender and elongate, about three times as long as wide; resembling Polybia group of wasps
P. pedicellata
P. townsendii
POLYBIOMYIA Shannon (pg. 448) (1W, 9N) P. pedicellata Williston
8(1). Face distinctly produced forward into a long snout; R4+5 and costa meeting behind apex of wing.
R. nasica RHINGIA Scopoli (pg. 342) (1W, 1N) R. nasica Say 8 Face not distinctly produced forward into a long snout 9
9(8). R4+5 with spur extending into R5 cell; weak-flying ground-frequenting species
MICRODON Meigen (pg. 196) (21W, 31N) M. aurulentus (Fabricius) M. baliopterus Loew M. coarctatus Loew M. cothurnatus Bigot M. craigheadii Walton M. diversipilosus Curran M. fulgens Wiedemann M. fuscipennis (Macquart) M. globosus (Fabricius) M. megalogaster Snow M. ocellaris Curran M. painteri Hull M. ruficrus Williston M. rufipes (Macquart) M. scutifer Knab M. tristis Loew M. viridis Townsend M. scitula (Williston) may have moved to BLERA M. pseudoglobosus Curran likely within M. globosus M. conflictus Curran status unknown M. champlaini Curran may be within tristus
9. R4+5 without such spur
10
10(9). M1+2 with upward spur into R5 cell (see wing above); abdomen narrowed at second segment; antennae elongate
M. breviventris
MIXOGASTER Macquart (pg. 235) (8W, 3N) M. breviventris Kahl M. delongi Johnson M. johnsoni Hull M. cubensis Curran probably not Nearctic Four new species from Weems not nameable
10. M1+2 without spur into R5 cell
11
11(10). M1 strongly recurrent, a stump of M2 present, R5 cell longest in middle and usually with an appendage at this point, stigmatic crossveins absent; antennae short; eyes usually sparsely pilose, males holoptic; hind femora and tibiae without cicatrices, the tibiae usually compressed basally to a non-setate knife edge; small (5-8 mm), weak-flying ground-frequenting species
E. tuberculatus
EUMERUS Meigen (pg. 256) (2W, 3N) E. strigatus (Fallen) E. tuberculatus Rondani
11. Not having the above combination of characters 12
12(11). Abdomen dark, with two large oval yellow spots on second tergite, four spots on third tergite, and a pair of lunate spots on fourth tergite; fairly large flies (14-16 mm); R4+5 with shallow loop into R5 cell.
S. lata CONDIDEA (Now Sericomyia) Coquillett (No species in Weems' keys other than here. S. lata Coquillett in Nearctica)
12. Abdomen not so marked, not such flies 13
13(12). Antennae remarkably elongate, with first two segments almost equal in length, third segment short, less than half length of first segment; mesonotum black, with bio interrupted vittae forming four elongate, yellowish spots; scutellum broadly yellow apically; abdomen with alternating black and yellow fasciae
S. vittata
SPHECOMYIA Latreille (pg. 435) (1W, 8N) S. vittata Wiedemann
13. Antennae not remarkably elongate, or if elongate then thorax without medial pair of interrupted yellow vittae 14
14(13). Mesonotum and abdomen mostly dark, with yellow markings of short, squamose pile; wings darkened on anterior border, distinctly so on apical half of anterior border; R4+5 deeply looped into R5 cell
MEROMACRUS Rondani (2W, 4N) M. acutus (Fabricius) M. ruficrus (Wiedemann)
14. Mesonotum and abdomen without yellow markings of short, squamose pile, or if so then wings are not darkened on anterior border and R4+5 not deeply looped into cell 15
15(14) Humeri bare, or with a few hairs along posterior margin, often mostly concealed by occiput; femora simple, bases without setae; bases of tibiae rounded; r-m crossvein before middle of 1st M2 cell (except in some Baccha)
16
15. Humeri pilose; femora frequently enlarged or tibiae modified; bases of femora often with setae; position of r-m crossvein variable
16(15). Antennae fairly elongate, usually porrect, as long as or longer than distance from vertex to distal end of antennal process; abdomen convex, oval, and emarginate, with bright yellow, medially interrupted fasciae; fairly large flies (10-14 mm. in length)
C. fasciolatum
C. integre
CHRYSOTOXUM 2nd Meigen (pg. 191) (4W, 12N) C. laterale Loew C. perplexum Johnson C. pubescens Loew C. plumeum Johnson fate unknown
16. Antennae short, not as long as distance between apex of head and distal end of antennal process, or if slightly elongate (figs. 77, 81), abdomen is not convex and emarginate or flies are small (3-6 mm. in length)
17
17(16). Antennae slightly elongate, third segment about three times as long as first; shape of third segment at least three times as long as wide; front of female much narrower than face; abdomen convex and cylindrical or broad and micropunctate; broader species have trace of emargination; very small files (3-6 mm. in length)
P. haemorrhous
PARAGUS Fabricius (pg. 262) (2W, 8N) P. bicolor (Fabricius) likely returned to within angustifrons P. tibialis (Fallen) likely back to P. haemorrhous Meigen
17. Larger flies, more than 3-6 mm. in length, or if small, antennae are not at all elongate and abdomen is not convex and cylindrical or micropunctate 18
18(17). Abdomen emarginate at least upon fourth and fifth tergites, often indistinctly so, caused by a sublateral crease on sides of abdomen; in some species sublateral crease may be restricted to terminal tergites
E. volucris 19 18. Abdomen non-emarginate, tergites rolled downward laterally
19(18). Metasternum pilose, hairs sometimes scant 20 19. Metasternum bare or pubescent 21
20(19). Hypopygium greatly enlarged, shining, asymmetrical as seen from above (see right image on 18), styles very long; fifth abdominal tergite half as long fourth in female, and mesonotuni wholly dark, shining; metasternum quite pilose
E. volucris
E. volucris
EUPEODES Osten Sacken (pg. 94) (1 W, 28 N) genus includes Weems METASYRPHUS species now He places here only E. volucris Osten Sacken
20. Hypopygium not greatly enlarged, styles of normal length; metasternum sparsely pilose; if fifth tergite of female is about half as long as fourth, abdomen has sub-parallel sides and front is not whitish yellow immediately above antennae or mesonotum is yellow laterally
E. emarginatus
E. grossulariae
EPISTROPHE Walker (pg. 110) (8 Weems, 7 N) E. emarginatus (Say) E. grossulariae Meigen E. metcalfi Fluke E. nitidicollis (Meigen) E. xanthostomus (Williston) E. divisus (Williston) fate unknown E. felix (Osten Sacken) fate unknown E. invigorus (Curran) fate unknown
21(19). Abdomen oval (See left image at 18); sides of mesonotum never sharply marked with bright, opaque yellow, although in a few species sides are dull yellowish 22 21. Abdomen cylindrical, slender, spatulate or petiolate; sides of mesonotum sometimes marked with bright opaque yellow
22(21). Lower lobe of squamae pilose above
S. torvus
SYRPHUS Fabricius (pg. 80) (7 W, 12 N) S. knabi Shannon S. rectus Osten Sacken S. ribesii (Linnaeus) S. torvus Osten Sacken S. vitripennis Meigen includes Xylota bigelowi Curran S. vittafrons Shannon subspecies of ribesii
22. Lower lobe of squamae pubescent above 23
23(22). Head, particularly the front, inflated; eyes pilose; wings glassy, villi absent or nearly so
S. pyrasti SCAEVA Fabricius (Weems included this genus in the key but listed no SE species. Nearctica lists one species S. pyrasti Linnaeus)
23. Front not inflated; eyes pilose or bare; wings villose
24
24(23). Second abdominal tergite with very large, oblique spots; metasternum bare
DIDEA Macquart (pg. 118) (1W, 3N) D. fuscipes Loew
24. Second abdominal segment not with very large, oblique, yellow spots; metasternum bare or pilose 25
25(24). Eyes pilose DASYSYRPHUS Enderlein (pg. 95) (3 W, 7N) includes D. arcuata Fallen which is likely now under D. venustus Meigen and D. osburni (Curran) which is likely back in D. amalopsis Osten Sacken 25. Eyes bare 26
26(25). Metasternum bare; abdomen oval, distinctly emarginate, penis sheath ribbed
M. wiedemanni
METASYRPHUS Matsumura and Adachi (pg. 85) (8 W, 0 N) Now part of EUPEODES includes E. lapponicus (Zetterstedt) E. latifasciatus Macquart E. medius Jones E. ochrostomus (Zetterstedt) E. perplexus Osburn E. pomus (Curran) M. wiedemanni and vinelandi appear to be returned to subspecies of Eupeodes americanus Wiedemann
26. Metasternum bare or pilose; abdomen oval, indistinctly emarginate
EPISTROPHE Walker (pg. 110) (8 Weems, 7 N) E. emarginatus (Say) E. grossulariae Meigen E. metcalfi Fluke E. nitidicollis (Meigen) E. xanthostomus (Williston) E. divisus (Williston) fate unknown E. felix (Osten Sacken) fate unknown E. invigorus (Curran) fate unknown
27(21). Abdomen petiolate, base considerably constricted, emarginate only upon terminal tergites BACCHA Fabricius (pg. 160) (see 34 31) 27. Abdomen cylindrical, spatulate, or ovate-spatulate, and at least wider subapically than basally 28
28(27). Moderately large black flies, brightly marked with yellow, or with red and yellow; sides of mesonotum sharply, brightly and contrastingly marked with yellow 29 28. Not as above; comparatively slender or small flies 30
29(28). Abdomen large, cylindrical
DOROS Meigen (pg. 121) (1W, 1N) D. aequalis Loew
29. Abdomen flattened, spatulate, brightly marked with yellow, or with red and yellow XANTHOGRAMMA Mik (pg. 119) (1W, 1N) X. flavipes (Loew)
30(28). Face produced forward on lower half or two-thirds, peaked or conical, tubercle often laterally compressed
T. geminatus
MESOGRAPTA Loew (pg. 122) (19W, 0N) most of Weems species now in TOXOMERUS and many were determined not to be Nearctic TOXOMERUS species retained now including T. arethusa (Hull) T. basilaris (Wiedemann) T. boscii (Macquart) T. floralis (Fabricius) T. geminatus (Say) T. jussiaeae (Vige) T. marginatus (Say) T. politus (Say) T. parvula (Loew) T. planiventris (Loew) T. slossonae (Curran) M. arcifera (Loew) apparently not Nearctic M. duplicata (Wiedemann) probably not Nearctic M. flavocuneus (Hull) moved to subspecies of basilaris M. lachrymosa Bigot apparently not Nearctic M. mutuum (Say) fate unknown M. pulchella (Macquart) apparently not Nearctic M. subannulata (Loew) apparently not Nearctic One new species from Florida, name not established
30. Face not produced forward, short and tuberculate, or non-tuberculate and rounded and retreating in profile
B. fuscipennis
BACCHA Fαbricius (pg. 160) (see 34 (31))
31(18). Metasternum pilose, hairs sometimes scant 32 31. Metasternum bare or pubescent 34
32(31). Epistoma and subtuberculate portion of face produced forward, whole lower two-thirds of face produced and blunt, epistoma but little or not at all diagonally elevated, oral opening narrow and elongate; hypopygium greatly enlarged and usually oval-bulbous; male with abdomen cylindrical
S. robusta
SPHAEROPHORIA Lepeletier and Serville (pg. 155) (5W, 16N) S. cleoae Metcalf S. novaeangliae Johnson S. cylindrica (Say) probably within contigua S. menthastri (Linnaeus) probably within scripta S. robusta Curran probably within scripta
32. Face short, tubercle low, oral tip of epistoma less prominent forward than tubercle
33
33(32). Sides of mesonotum dark in ground color, notopleura sometimes golden pollinose or micropubescent; fourth abdominal tergite usually with oblique spots and paired medial vittae ALLOGRAPTA Osten Sacken (pg. 150) (3W, 4N) A. exotica Wiedemann A. obliqua (Say) One species only in Fl. keys
33. Sides of mesonotum yellow in ground color; fourth abdominal tergite not with oblique spots and paired medial vittae (see second face at 32)
EPISTROPHE Walker (pg. 110) (See 20)
34(31). Abdomen petiolate, constricted or narrowed subbasally, or at least narrowly spatulate or abdomen gradually and slightly widening from base; wings sometimes distinctly infuscated in part
B. elongata
O. dimidiata
O. fascipennis
O. fuscipennis
Pseudodoros clavatus
BACCHA Fabricius (pg. 160) (11W, 4N) Several of Weems Bacchus are now under new genera only Baccha nepenthe Hull remains in Baccha Ocyptamus costatus (Say) Ocyptamus dimidiata (Fabricius) Ocyptamus fascipennis (Wiedemann) Ocyptamus fuscipennis (Say) Ocyptamus gastrostacta (Wiedemann) Pseudodoros clavatus (Fabricius) B. calypso (Hull) fate unknown B. notata (Loew) not Nearctic B. obscuricornis Loew fate unknown B. scutellata (Loew) probably not Nearctic
34. Abdomen oval, or with approximately parallel sides; wings usually hyaline, or nearly so 35
35(34). Eyes pilose or bare; abdomen usually nearly cylindrical; species with predominant fascia or paired spots of brown or yellow; anterior fore femora, tibiae and tarsi always simple; face almost always yellow; sides of mesonotum usually yellowish 36 35. Eyes bare; abdomen oval or with parallel sides; face and thorax without lighter color; mostly black, brown, or metallic-black species 37
36(35). Abdomen fairly slender or with paired yellow spots; edges of abdominal tergites rolled. Now split into five genera as below. Meliscaeva with one species has a minute row of black dots on posterior edge of hindwing. Melangyna has no hairs on anterior anepisternum. Eriozona has dense eye hair.
Melangyna lasiopthalma
STENOSYRPHUS Matsumura and Adachi (pg. 99) (10W, 0 N) no longer a valid genus and Weems species divided into 5(!!) genera ERIOZONA laxa Osten Sacken MELANGYNA arctica (Zetterstedt) Melangyna cincta Fallen Melangyna fisheri (Walton) |
