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Key taken from Howard Vincent Weems unpublished PhD.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


1.         Antennae with a terminal style


M. villosus



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(2’).   First two antennal segments short, third compressed laterally with terminal style on produced upper angle (see first image at 1)


3’.        Antennae cylindrical, first two segments elongate, third tapering and bearing a small terminal style





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



(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


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






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(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(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(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(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(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(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



(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(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)





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(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(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


18’.      Abdomen non-emarginate, tergites rolled downward laterally




19(18). Metasternum pilose, hairs sometimes scant


19’.      Metasternum bare or pubescent




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


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(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(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(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(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(27’). Moderately large black flies, brightly marked with yellow, or with red and yellow; sides of mesonotum sharply, brightly and contrastingly marked with yellow


28’.      Not as above; comparatively slender or small flies




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


31’.      Metasternum bare or pubescent




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(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(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


35’.      Eyes bare; abdomen oval or with parallel sides; face and thorax without lighter color; mostly black, brown, or metallic-black species




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)

MELISCAEVA cinctella (Zetterstedt)

OCYPTAMUS jactator (Loew)

PARASYRPHUS genualis (Williston)

Parasyrphus semiinterruptus (Fluke)

S. Johnsoni Curran of Weems likely

moved into Parasyrphus genualis (Williston)

S. mentalis (Williston) unknown fate

S. albipunctatus Curran not eastern and fate unknown


36’. Abdomen oval, not slender; edges of abdomen rolled and yellow

fascia entire, or indistinctly emarginate


EPISTROPHE Walker (pg. 110)

(8 Weems, 7 N)

(See 20’)



37(35’). Lower two-thirds of face produced forward and peaked, occasionally reaching beyond antennae (including subgenus Toxomerus); face usually yellowish


MESOGRAPTA Loew (pg. 122)

(See split 30)


37’.      Face short, not produced forward and peaked or if produced forward, face is greenish black, shining, thinly covered with grayish pollen, pollen on sides forming indistinct ripples




38(37’). Anterior tibiae of males dilated, or their basitarsi enlarged and expanded (see below), those of females usually a little widened



P. stegmus


PLATYCHEIRUS Lepeletier and Serville (pg. 181)

(5W, 60+N)

P. quadrata (Say)

P. scamboides Curran

P. scambus (Staeger)

Very difficult group apparently

P. erraticus Curran likely within clypeatus or hyperboreus

P. peltatus (Meigen) within P. albimanus (Fabricius)

Weems PYROPHAENA rosarum (Fabricius) (pg. 189)

which he apparently left out of his genus key

is now Platycheirus rosarum (Fabricius)


38’.      Anterior tibiae and tarsi simple and normal in bath sexes


M. mellinum


MELANOSTOMA Schiner (pg. 177)

(3W, 6N)

M. angustatum Williston

M. obscurum (Say) fate unknown

M. pictipes Bigot probably included in M. mellinum Linnaeus



39(15’). Stigmatic crossvein usually absent; r-m crossvein wholly before middle of 1st M2 cell; relatively bare groups of flies for the most part




39’.      Stigmatic crossvein usually present; r-m crossvein usually near or beyond middle of 1st M2 cell; bare or distinctly pilose flies





40(39). M1 vein strongly recessive, costa and end of R4+5 usually quite recessive, Rs always with slender bristles; arista, with rare exceptions, plumose; metasternum always pilose; femora simple, base of hind tibiae rounded; face tends to be produced downward or rarely diagonally downward, usually with a tubercle






40’       The r-m crossvein usually well before middle of 1st M2 cell, rarely or never beyond it; radial sector bristles, facial tubercle, and metasternal pile sometimes absent; arista rarely plumose, or if plumose, neither M1 nor costa are recessive; femoral setae usually present upon front femora, sometimes upon all femora







41(40). M1 only moderately recessive, costa but little or not at all recessive, second anal vein always bent and concave on anterior sides, r-m crossvein just before middle of 1st M2 cell; abdomen with one or more pairs of ob1ique or transverse yellow spots; face produced below


S. chrysotoxoides


SERICOMYIA Meigen (pg. 368)

(2W, 11N)

S. carolinensis (Metcalf)

S. chrysotoxoides Macquart


41’.      M1 strongly recessive, costa and end of R4+5 usually quite recessive, second anal vein straight or concave on its posterior side, r-m crossvein always before middle 1st M2 cell; abdomen convex, oval; robust flies


V. nigra




42(41’) Face tri-tuberculate, with swelling mesally and on each side scutellum with preapical depression; metallic greenish or bluish-green flies


O. obesa

ORNIDIA Fabricius (pg. 366)

(1W, 1N)

O. obesa (Fabricius)


42’.       Face not tri-tuberculate, usually with distinct medial tubercle only; scutellum without any trace of concavity; small to large, robust species


VOLUCELLA. Geoffroy (pg. 347)

(14W, 33N)

V. abdominalis Wiedemann

V. anastasia Hull

V. barei Curran

V. eugenia Williston

V. nigra Greene

V. pallens Wiedemann

V. pusilla Macquart

V. vesicularia Curran

V. victoria Williston

V. evecta Walker to V. bombylans Linnaeus

V. americana Johnson within V. bombylans Linnaeus

V. fasciata Macquart likely within V. pusilla Macquart

V.  vacua (Fabricius) likely not Nearctic




43(40’). Face with tubercle between epistoma and antennae, although sometimes small; epistoma not sharply produced



43’.      Face without tubercle; epistoma sometimes protruding






44(43). M1 meeting R4+5 at or near apical margin of wing; face of males tuberculate, of females non-tuberculate; thorax and abdomen clothed with squamulae or with normal pile


M. strigilata

female                                                              male


M. varipes


MYOLEPTA Newman (pg. 334)

(5W as Myiolepta, 7N)

M. nigra Loew

M. strigilata Loew

M. varipes Loew

M. pretiosa Hull probably within M. varipes Loew

One new species from Weems. M. camillae Weems


44’.      M1 meeting R4+5 some distance back from apical margin of wing





45(44’). Hind femora greatly thickened; lower face conically and diagonally produced forward and downward for a considerable distance, facial tubercle subordinate



C. bella


CYNORHINELLA Curran (pg. 292)

(1W, 3N)

C. longinasus Shannon


45’.      All femora comparatively quite slender; lower face not produced; eyes pilose or bare; arista plumose, pubescent, or bare


C. prima


C. sialia


C. capillata


CHEILOSIA Meigen (pg. 265)

(16W, 100+N)

C. caltha (Shannon)

C. capillata Loew

C. cyanescens Loew

C. cynoprosopa Hull & Fluke

C. lasiopthalma Williston

C. leucoparea Loew

C. pallipes Loew

C. hoodiana (Bigot)

C. pontiaca Shannon

C. prima Hunter

C. primoveris Shannon

C. shannoni Curran

C. swannanoa Brimley

C. tristis Loew

C. willistoni Snow

C. slossonae Shannon likely within prima




46(43’). Radial sector with slender bristles; r-m crossvein near middle of 1st M2 cell or mesonotum vittate; sometimes with strong bristles on mesonotum and scutellum


F. dives



46’.      Radial sector without bristles




47(46). Aeneous flies, with very strong bristles on mesonotum and scutellum (see bristles above); face barely concave on upper half


F. dives


FERDINANDEA Rondani (pg. 284)

(2W, 5N)

F. dives (Osten Sacken)

F. nigripes (Osten Sacken)


47’.      Not aeneous species, usually luteous in color; mesonotum usually vittate; mesonotum and scutellum only with strongly developed pile; femora and tibiae more slender with less heavy spines; antennae located below middle of eyes


B. vacua

BRACHYOPA Meigen (pg. 286)

(8W, 14N)

B. daeckei Johnson

B. diversa Johnson

B. flavescens Shannon

B. media Williston

B. nigricauda Curran

B. notata Osten Sacken

B. perplexa Curran

B. vacua Osten Sacken




48(46’). Face straight or receding in profile, epistoma never produced, eyes pilose; hind femora simple, or rarely a little swollen, sometimes microdenticulate distally; M1 never meeting R4+5 at apical margin of wing. Weems' species now divided into several genera. Heringia has a ventral spur on the hind trochanter. Pipiza has simple hind trochanters. Trichopsomyia has long erect hairs on the anterior anepisternum.


P. femoralis


P. quadrimaculata


P. femoralis


PIPIZA Fallιn (pg. 294)

(15W, 16N)

P. femoralis Loew

P. nigripilosa Williston

P. quadrimaculata (Panzer)

Some species moved to new genera TRICHOPSOMYIA

T. apisaon (Walker)

T. australis (Johnson)

T. banksi (Curran)

T. recedens (Walker)

Some species moved to genus HERINGIA

H. salax (Loew)

Some species moved to NEOCNEMODON

N. calcarata (Loew)

N. cevelata (Curran)

N. coxalis (Curran)

N. intermedia (Curran)

N. myerma (Curran)

N. pisticoides Williston

N. squamulae (Curran)


48’.      Face either concave and produced diagonally forward upon lower half, or face straight above with epistoma projecting (see third and fourth faces below), or antennal prominence broadly and distinctly produced; hind femora simple, or if thick, they are very thick and denticulate


Myolepta camillae






49(48’). Front produced into a rather conspicuous antennal protuberance; eyes dichoptic in male; scutellum subrectangular; apex of abdomen asymmetrical to the right in male


L. aerea

LEJOTA Rondani (pg. 341)

(1W as Leiota, 2N)

L. aerea (Loew)


49’.      Front not remarkably produced into antennal protuberance; scutellum not subrectangular; apex of abdomen not conspicuously asymmetrical in male




50(49’). M1 usually meeting R4+5 at or very near apical margin of wing; face concave upon upper half, projecting bluntly, obconically, and diagonally forward upon lower half, male face usually with a tubercle (see paired faces at 48); hind femora moderately thickened, usually spinose below; head, thorax or abdomen, or all three, sometimes clothed with flattened squamulae, sometimes with short, soft or setaceous pile


M. strigilata

MYOLEPTA Newman (pg. 334)

(5W as Myiolepta, 7N)

M. nigra Loew

M. strigilata Loew

M. varipes Loew

M. pretiosa Hull probably within M. varipes Loew

One new species from Weems.


50’.      M1 meeting R4+5 distinctly before apical margin of wing; face straight or slightly concave upon upper half, but epistoma always slightly to distinctly produced forward; antennae short or long, never with flattened squamulae








51(50’). Small (3.5-5 mm. in length), slander, nearly bare, black or metallic green flies, with or without reddish or yellow on abdomen; antennae often slightly elongate, third segment elongate, with bare arista near middle (see first face above at 50); eyes bare, without linear patterns; wings with outer backward angle of R5 cell almost rectangular


N. globosa


N. metallica


NEOASCIA Williston (pg. 332)

(4W, 10N)

N. albipes (Bigot)

N. distincta Williston

N. globosa (Walker)

N. metallica (Williston)


51’.      Larger flies (more than 5 mm. in length), or with abdomen broadly oval, flattened or convex; eyes pilose or bare, sometimes with distinct linear patterns; antennae elongate or short





52(51’). Abdomen elongate, slender, usually constricted subbasally, often quite petiolate; epistoma quite often considerably produced (see face at 51); antennae always short, third segment round or short-oval; arista usually pubescent, longer than third antennal segment; lower angle of R5 cell rounded; eyes bare


S. lobata


S. keeniana


SPHEGINA Meigen (pg. 319)

(11W, 22N)

S. biannulata Malloch

S. campanulata Robertson

S. flavimana Malloch

S. flavomaculata Malloch

S. infuscata Loew

S. keeniana Williston

S. lobata Loew

S. lobulifera Malloch

S. rufiventris Loew

S. brimleyi Shannon likely within infuscata Loew

S. monticola Malloch status unknown


52’.      Abdomen short, oval, compact or flattened; antennae short or often quite elongate; eyes pilose or bare, sometimes with distinct maculation


O. nitida




53(52’). Eyes densely pilose; face straight and retreating to epistoma, which is produced a short distance; antennae short or moderately long; abdomen convex, oval; spurious vein absent


P. thatuna


PSILOTA Meigen (pg. 317)

(2W, 3N)

P. buccata (Macquart)

P. thatuna Shannon


53’.      Eyes bare, unicolorous, unimaculate, or with zig-zag or tortuously winding maculation, particularly brilliant in life (see face at 52); abdomen oval, usually wide, and much flattened; spurious vein usually present, although often faint


C. antitheus


O. pulchella


CHRYSOGASTER Meigen (pg. 309)

(7W, 12N)

C. inflatifrons Shannon

C. texana Shannon

Some species moved to ORTHONEVRA 2nd

O. nitida (Wiedemann)

O. pictipennis (Loew)

O. pulchella (Williston)

C. nigripes Loew reverted to C. antitheus Walker

C. greenei Shannon likely reverted to within C. texana Shannon



54(39’). All femora with well-developed basal patches of setae, hind tibiae usually with knife-edge; metasternum always pilose.; R4+5 always with loop, 2A strongly bent, anterior side concave, radial sector bristles usually present




54’.      Only first or second femora with femoral setae; hind tibiae often with knife-edge upon basal third; metasternum with or without pilo; usually without deep loop, although characteristically sinuous, radial sector bristles occasionally present






55(54). R1 cell always closed (see first two wings at 54); sparsely to thickly pilose flies; abdomen variously marked with light and dark fascia or spots. Divided into three genera now. Palpada always have bare arista and have eye hair above. Eristalinus has dark spots on the eye. Most Eristalis have densely hairy eyes.



P. agrorum                                                             P. albifrons  



E. arbustorum                                                          E. dimidiatus    



E. saxorum                                                        E. transversus


ERISTALIS Latreille (pg. 472)

(15W, 23N)

E. arbustorum 2nd Linnaeus

E. barda (Say)

E. dimidiata Wiedemann

E. obscurus Loew

E. saxorum Wiedemann

E. tenax (Linnaeus)

E. texanus Hull

E. transversa Wiedemann

E. bastardii Macquart probably within E. barda (Say)

E. latifrons Loew reverted to E. stipator Osten Sacken

E. aeneus (Scopoli) moved to ERISTALINUS Rondani

 Some species moved to PALPADA Macquart

P. agrorum (Fabricius)

P. albifrons Wiedemann

P. vinetorum (Fabricius)

One new species named by Weems status unknown.


55’.      R1 cell always open






56(55’). M1 strongly recurrent (see first wing just above); arista bare; hind femora much thickened, bearing large lateral plate apically which may have one or more teeth; robust, shaggy, long-pilose flies



MERODON Meigen (pg. 469)

(1W, 1N)

M. equestris Fabricius


56’.      M1 never recurrent (see second wing at 55); hind femora slender or thick, but without plate bearing a tooth






57(56’). Stigmal crossvein absent (see second wing at 55); hind femora without spur; thorax vittate

HELOPHILUS Meigen (pg. 450)

(2W, 33N)

H. fasciatus Walker

H. latifrons Loew


57’.      Stigmal crossvein present, or in last stages of development; hind femora with or without spur; thorax with or without vittae


M. posticata




58(57’). Face usually deeply produced below, fronto-antennal region never prominent, face not attenuated and conical; thorax unicolorous; abdomen densely pilose; rather large, woolly, long-pilose flies (see wing just above)


M. posticata


M. bautias

MALLOTA Meigen (pg. 464)

(5W, 11N)

M. bautias (Walker)

M. bipartita (Walker)

M. mississippiensis Hull

M. posticata (Fabricius)

M. separata Hull


58’.      Face not deeply produced below, fronto-antennal region sometimes prominent; rather short-pilose flies


L. currani




59(58’). Abdomen broad and comparatively flat in both sexes, usually short, oval, not twice as long as wide; hind tibiae truncate at apex


H. laetus male


PARHELOPHILUS Girschner (pg. 460)

(5W, 0N)

All Weems' species moved to HELOPHILUS

H. anniae (Brimley)

H. divisus (Loew)

H. flavifacies (Bigot)

H. integer (Loew)

H. laetus (Loew)


59’.      Abdomen comparatively slender and subcylindrical, especially in male, with parallel sides or tapering, over twice as long as wide; hind tibiae produced below at apex


H. currani



LEJOPS Rondani Now in HELOPHILUS (pg. 452)

(5W, 0N)

All Weems' species moved to HELOPHILUS

L. chrysostomus (Wiedemann)

L. distinctus (Williston)

L. orion Hull

L. relictus Curran and Fluke

One new species from Weems fate unknown



60(54’). Face tricarinate, not jutting out beyond base of antennae, keel vertical and straight, or slightly convex; hind femora swollen, greatly enlarged; wings hyaline, with R4+5 and M1 meeting before apex of wing near costal border, stigmal crossvein absent; medium-sized (8-12 mm. in length), nearly bare species, chiefly black, with yellow or orange markings on abdomen


T. quadrata



T. quadrata


TROPIDIA Meigen (pg. 400)

(4W, 8N)

T. albistylum Macquart

T. calcarata Williston

T. mamillata Loew

T. quadrata (Say)


60’.      Face never with well-developed medial keel and lesser face cheek keels; without above combination of characters




61(60’). Mesonotum and abdomen wholly and fairly thickly long pilose; metasternum pilose; third antennal segment deeper than long, face produced below


C. verbosa

CRIORHINA Meigen (pg. 437)

(3W, 15N)

C. nigriventris Walton

C. verbosa (Walker)

C. intermedia Johnson likely within nigriventris Walton


61’.      Mesonotum and abdomen not wholly and thickly long or if moderately or thickly pilose, metasternum is pubescent; antennal segment usually oval or elongate, longer than deep




62(61’). Hind femora greatly swollen, with numerous spines below, black, with base and a usually incomplete ring near middle reddish yellow; rather small, slender flies (about 7-8 mm. in length), nearly bare, black, with yellow markings; head hemispherical, face weakly carinate or with obtuse, longitudinal ridge, never with a keel, epistoma s1ightly produced; scutellum thin on its edge



S. pipiens


SYRITTA Lepeletier and Serville (pg. 398)

(1W, 2N)

S. pipiens (Linnaeus)


62’.      Not such flies; face not carinate or ridged; hind femur slender or swollen, never colored as above




63(62’). Third antennal segment as deep as or deeper than long, typically obliquely oval; face concave, eyes of male narrowly separated; lower face diagonal, elongate and subtruncate; metasternum pubescent; scutellum with ventral fringe; hind femora elongate, thick, tibiae excavated basally; medium to large (7-16 mm. in length), elongate, rather long pilose flies, sometimes thickly short pilose on mesonotum and sparsely pilose, shining bluish or black on abdomen



B. oarus


B. femoratus


B. oarus


BRACHYPALPUS Macquart (pg. 390)

(5W, 8N)

B. amithaon (Walker)

B. margaritus Hull

B. oarus (Walker)

Several moved to CHALCOSYRPHUS

C. inarmatus (Hunter)

C. metallifera (Bigot)


63’.      Third antennal segment either orbicular or elongate; almost exclusively short pilose, rather bare flies, occasionally long pilose at base of abdomen; not having above combination of characters




64(63’). The r-m crossvein quite oblique, and near end of 1st M2 cell, Cu1 cell with very long petiole drawn out along wing margin; large flies (11-12 mm), often brightly marked





64’.      The r-m crossvein less oblique and at or slightly beyond middle of 1st M2 cell, Cu1 cell with short straight petiole; brightly colored or somber files







65( 64’). Hind femora slender, with an sub-apical tooth; eyes with vertical, irregular stripes or blotches; first and second antennal segments slightly to distinctly elongate; metasternum with an obtuse blunt spur anteriorly; wasp-like flies



S. hamifera



SPILOMYIA 2nd 3rd Meigen (pg. 419)

(5W, 13N)

S. fusca Loew

S. longicornis Loew

S. texana Johnson

S. hamifera Loew status unknown

S. quadrifasciata (Say) status unknown


65’.      Hind femora often thickened, with or without subapical tooth; eyes uniformly colored; antennae scarcely or not at all elongate; face usually concave, front produced; R1 cell closed, M1 and R4+5 meeting near costal border before apex of wing; R4+5 gently looped into R5 cell; large (16-21 mm), brightly-colored flies



M. virginiensis


MILESIA Latrelle (pg. 415)

(2W, 3N)

M. scutellata Hull

M. virginiensis (Drury)




66(64’). Bright, yellow-pollinose, wasp-like flies, with yellow-pollinose markings on thorax and abdomen; first and second antennal segments always quite short; face usually quite concave, especially in females, less so in males; males often with weak tubercle, face never deeply produced; anterior wing border dark




TEMNOSTOMA Lepeletier and Serville (pg. 425)

(9W, 10N)

T. acra Curran

T. alternans Loew

T. balyras Walker

T. excentrica Harris

T. trifasciatum Robertson

T. venustum Williston

T. pictulum Williston possibly within excentrica Harris

T. apiforme (Fabricius) likely within vespiformis Linnaeus


66’.      Never yellow pollinose, although sometimes marked with yellow




67(66’). Abdomen with large transverse or oblique yellow spots on at least second, third and fourth tergites; fronto-antennal region moderately to greatly produced; face deep, nearly straight, but slightly concave; M1 and R4+5 meeting before apical margin of wing, anterior wing border dark




SOMULA Macquart (pg. 412)

(2W, 2N)

S. decora Macquart

S. mississippiensis Hull


67’.      Abdomen not with large, transverse or oblique, yellow spots on second, third and fourth tergites




68(67’). Metasternum pubescent; lower face usually prominent; abdomen wholly shining black or with yellowish markings; legs never greatly thickened; M1 and R4+5 confluent at or near apex of wing


B. umbratilis


B. confusa


B. badia


CYNORHINA Williston Now BLERA (pg. 404)

(10W, 0N)

All Weems' species moved to BLERA

B. analis (Macquart)

B. badia (Walker)

B. confusa (Johnson)

B. metcalfi (Curran)

B. nigra (Williston)

B. notata (Wiedemann)

B. pictipes (Bigot)

B. umbratilis (Williston)


68’.      Metasternum pilose or pubescent; third antennal segment sometimes moderately elongate; hind femora sometimes swollen; face concave; mostly dark, metallic flies




69(68’). Metasternum pubescent


69’.      Metasternum pilose




70(69). Posterior margins of abdominal tergites with thick, matted, subappressed border of pile; large, aeneous or cupreous flies with dense, short, brownish-yellow or golden pile; abdomen with aeneous crossbands


CHRYSOSOMIDIA Curran (pg. 395)

(1W, 0N)

C. aepalius (Walker) moved to HADROMYIA


70’.      Posterior margins of abdominal tergites not with conspicuous, matted borders of pile; less strikingly metallic flies, abdomen not opaque black with brilliant metallic crossbands



X. barbatus


XYLOTA Meigen (pg. 371)

(18W, 29N)

X. analis Williston

X. angustiventris Loew

X. annulifera Bigot

X. artemita Hull

X. bicolor Loew

X. ejuncida Say

X. hinei (Curran)

X. quadrimaculata Loew

Most moved to CHALCOSYRPHUS 2nd

X. baton Walker probably moved to

within CHALCOSYRPHUS as C. nemorum Fabricius


C. althaea (Hull)

C. anthreas (Walker)

C. astarte (Hull)

C. libo (Walker)

C. metallica (Wiedemann)

C. pigra (Fabricius)

C. primavera (Hull)

C. vecors (Osten Sacken)

X. chalybea Wiedemann status unknown




71(69’). Hind femora compressed below on distal third or more into narrow, spiniferous ridges, straight but much thickened (figs. 113); abdomen not constricted basally



XYLOTA Meigen (pg. 371)

(see above)


71’.      Hind femora rounded below, without ridge; abdomen somewhat narrowed basally, especially in female






72(71’). Mesonotum ochraceous pollinose, thickly short brownish-yellow pilose (and left leg just above)

PTERALLASTES Loew (pg. 442)

(1W, 1N)

P. thoracicus Loew

72’.      Mesonotum not ochraceous pollinose




73(72’). Abdomen wide, flattened, scutellar fringe virtually absent; hind femora moderately thickened, hind tibiae with medial internal spur in male (right leg above and from Nearctic below)


T. literatus


TEUCHOCNEMIS Osten Sacken (pg. 397)

(2W, 2N)

T. bacuntias (Walker)

T. literatus (Loew)


73’.      Abdomen not especially widened and flattened; scutellar fringe well developed; bind femora considerably thickened, lower portion of face rather compressed laterally, the cheek-face angles distinct


BRACHYPALPUS Meigen (pg. 390)

(5W, 8N)

B. amithaon (Walker)

B. margaritus Hull

B. oarus (Walker)

Several moved to CHALCOSYRPHUS

C. inarmatus (Hunter)

C. metallifera (Bigot)




Species added after 1953

Unknown which, if any, are also eastern.


Chalcosyrphus cascadensis Weems 1965


Chrysogaster anniae Sedman 1966


Copestylum vittatum Thompson 1976


Eristalis beltrami Telford 1970

Eristalis californicus Nayar and Cole

Eristalis vandykei Nayar and Cole


Helophilus colei Wirth 1965


Mallota bequaerti Hull 1956


Melangyna coei Nielsen 1971

Melangyna vespertina Vockeroth 1980


Microdon abditus Thompson 1981

Microdon abstrusus Thompson 1981

Microdon adventitious Thompson 1981

Microdon albicomatus Novak 1977

Microdon carolae Capelle 1956


Ocyptamus loewi Sedman 1965


Paragus angustistylus Vockeroth 1986

Paragus arizonensis Vockeroth 1986

Paragus bispinosus Vockeroth 1986

Paragus cooveri Vockeroth 1986

Paragus longistylus Vockeroth 1986

Paragus variabilis Vockeroth 1986


Parasyrphus bulbosus Fluke 1954


Platycheirus hesperius Vockeroth 1990

Platycheirus hispidipes Vockeroth 1990

Platycheirus holarcticus Vockeroth 1990

Platycheirus jaerensis Nielsen 1971

Platycheirus latitarsis Vockeroth 1990

Platycheirus nearcticus Vockeroth 1990

Platycheirus nielseni Vockeroth 1990

Platycheirus octavus Vockeroth 1990

Platycheirus orarius Vockeroth 1990

Platycheirus oreadis Vockeroth 1990

Platycheirus pilatus Vockeroth 1990

Platycheirus protrusus Vockeroth 1990

Platycheirus pullatus Vockeroth 1990

Platycheirus rufigaster Vockeroth 1990

Platycheirus rufimaculatus Vockeroth 1990

Platycheirus russatus Vockeroth 1990

Platycheirus sabulicola Vockeroth 1990

Platycheirus setipes Vockeroth 1990

Platycheirus setitarsis Vockeroth 1990

Platycheirus spinipes Vockeroth 1990

Platycheirus stegnoides Vockeroth 1990

Platycheirus striatus Vockeroth 1990

Platycheirus thompsoni Vockeroth 1990

Platycheirus woodi Vockeroth 1990

Platycheirus yukonensis Vockeroth 1990


Sphaerophoria asymmetrica Knutson 1973

Sphaerophoria bifurcata Knutson 1973

Sphaerophoria brevipilosa Knutson 1973

Sphaerophoria longipilosa Knutson 1973

Sphaerophoria weemsi Knutson 1973


Sphecomyia columbiana Vockeroth 1965

Sphecomyia fusca Weisman 1964


Spilomyia citima Vocekroth 1958

Spilomyia foxleei Vockeroth 1958

Spilomyia oregonensis Nayar and Cole 1968

Spilomyia sayi Goot 1964


Syrphus sonorensis Vockeroth 1983