Key to the Bombyliidae
of the eastern US
1 Wing with 4 or rarely with 5 posterior cells. Includes species with posterior veins partly atrophied.
1’ Wing with only 3 posterior cells.
2 Abdomen long and slender, many times longer than wide; laterally compressed throughout its length, or more or less attenuate on the basal half or more. Metasternum oblique and often greatly and remarkably drawn out and extended posteriorly (Systropinae of Hull).
Systropus macer Loew 1863 is the only eastern species
2’ Abdomen robust, oval or subspherical, or abdomen short conate, attenuate apically but never extensively lengthened. Metasternum not drawn out extensively posteriorly; never more than normal in development.
3 Third antennal segment long but gradually attenuate, with a short, still more narrowed microsegment or style (Gerontinae of Hull).
Geron Meigen is the only genera in the east, with ten species
3’ Third antennal segment blunt and obtuse at apex, with a minute, subapical, subdorsal spine (Usinnae of Hull).
Apolysis sigma Coquillett 1902 is the only eastern species
4 Flies without a large, conspicuous cavity in the occiput. Occiput usually not extensive, or if thickened, the outer part slopes gradually away from the eye margin. Occiput not bilobate above, with deep, vertical, postocellar fissure. Middle of posterior eye margin almost always smooth, entire and continuous, without indentation; an indentation is very rarely present in this group.
4’ Flies with a large, central, deeply sunken cavity in the posterior occiput of the head. Note that this can be covered with hairs from the thorax, check closely. Posterior occiput is extensive and tumid posteriorly beyond the lateral dorsal eye margin. Occiput always bilobate above and with resultant deep, vertical postocellar fissure. Middle of lateral posterior eye margin with or without, more often with, an indentation, which occasions even greater exposure of the occiput. Indentation, when present, generally conspicuous, more rarely the eye margin is recessed forward on the entire upper half.
5 Lateral eye margin neither indented nor recessed forward above (Cylleninae of Hull).
Metacosmus exilis Coquillett 1891 is the only eastern species
5’ Lateral eye margin with distinct indentation or at least the upper half recessed forward.
6 Second longitudinal vein arising before the middle crossvein and at an acute angle, rarely with a bluntly rounded angle (Lomatiinae of Hull).
6’ Second vein arising opposite or close to middle crossvein or nearly so, and always at right angle (Exoprosopinae and Anthracinae of Hull).
(See other figures of wing veins for the following genera, confusing group) 6.05
6.00 Small, slender flies for the most part; abdomen elongate and gently tapered. Male genitalia large and terminal.
Aphoebantus cervinus Loew 1872 is only eastern species
6.00’ Flies small and blackish. Male genitalia recessive and concealed.
Ogcodocera leucoprocta Wiedemann 1828 is only eastern species
(Note there are three separations here at 6.05)
6.05 Third antennal segment without any sort of a separated style whatever; bears only a short spine. Two submarginal cells or three rarely. Claws without a basal tooth.
6.05’ Third antennal segment with a small, short, suture separated microsegment always bearing a tuft, usually a conspicuous tuft, or circlet of apical hairs. Two or rarely three submarginal cells. Face always strongly retreating and rounded below. Proboscis always short. Antennae always quite short, third segment often bulb-like.
Anthrax and Xenox with twelve and one species in the east
6.05’’ Third antennal segment with a distinctly separated spine-tipped or bristle-tipped style or microsegment, of variable length and thickness, which is separated by a suture, distinct from the base of the third segment. Three sometimes four submarginal cells. Proboscis long or short. Claws always with a long or short basal tooth.
Exoprosopa Coquillett with twelve species in the east
6.1 Second vein very strongly sigmoid on its outer section, both basally and apically.
Dipalta Osten Sacken with two species in the east
6.1’ Second vein narrowly curved and marginal cell slightly or moderately bulbous at the apex.
6.2 Face very strongly conical and pointed apically and covered with sparse, short, scattered setae. Anterior branch of third vein strongly bent backward and approximately at a right angle. Base of third antennal segment gently tapered and conical.
Neodiplocampta Curran with two species in the east
6.2’ Face rounded or conical. Curve or anterior branch of third vein rather shallow, at least not rectangularly rounded. Third antennal segment of various shapes.
6.3 Third segment of antennae short, small, onion-shaped, with long abruptly formed styliform portion which is linear, of uniform thickness, even threadlike. Face and proboscis, each long or short.
6.3’ Third antennal segment long or short conical, attenuate beyond the wide base; also rarely long and thick and scarcely tapered. Face and proboscis likewise variable, long or short.
6.4 The proboscis extends beyond the face and oral opening by at least half the length of the oral opening. Styliform part of third antennal segment long and slender. Foretibia with strong bristles. Hypopleuron bare or nearly so. Wings generally with the basal half dark.
Rhyncanthrax parvicornis Loew 1869 is the only eastern species
6.4’ Proboscis not projecting beyond oral opening. Face retreating and generally bluntly rounded. Hypopleural pile usually present. Front tibia generally spiculate with dark bristles. Base of wings blackish on the basal half or more with irregular margin to the black pattern posteriorly.
Hemipenthes Loew with nine species in the east
6.5 Wings hyaline, or very nearly so. Face rounded and retreating and the quite short proboscis does not project beyond the oral opening. Third antennal segment conical but very short, the style long and slender. The pulvilli are absent, the metapleural fringe dense, the basal comb large and often conspicuously silvery. Discal cell acute at apex. Anterior tibia with setae or even spines.
Villa Lioy with 18 species in the east
6.5’ Wings partly or wholly colored, or if nearly hyaline, the face is either prominent, or the third antennal segment is long conical. Face always more or less extended, bluntly rounded or conical or even sharply conical.
6.6 Front tibia spiculate in three rows. Face strongly projecting and conical, usually acutely conical. Third antennal segment long conical.
Paravilla Painter with five species in the east
6.6’ Front tibia relatively smooth. Claws small, rarely large. Face rounded anteriorly. Face bluntly triangular, or if subconical the wings are large and long.
6.7 Front with rather dense, erect, coarse, bristly hairs; face subconical, with similar hairs but more sparse. Both face and front usually without any appressed flattened hairs. Wings usually with extensive mottled pattern covering whole wing, with some hyaline spots; a few species with posterior margin and apex hyaline. Wings unusually large and elongate; first posterior cell characteristically narrowed toward the margin. Lower vein of discal cell bowed, with an angle, and usually with a long, characteristic, ventroapical spur vein or an antero-basal spur vein. End of discal cell acute. Anterior tibia smooth; anterior claws minute. Pulvilli absent.
Poecilanthrax Osten Sacken with seven species in the east
6.7’ At least the apical half or two thirds of wings clear. Wings relatively much smaller. Pattern of wing on basal half more or less solid and uniform, or with one to several subhyaline flecks, or dilutely hyaline with only the veins and costa of basal half blackish or brownish, or yellow. Discal cell below without angle and lower spur vein.
Chrysanthrax Osten Sacken with four species in the east
7 Prothorax prominent, bearing remarkably long, stout, straight or curved macrochaetae on lateral, dorsal or both portions. The anterior margin of the mesonotum and post-margin of the scutellum bear long, slender or stout, macrochaetae or bristles. Femora and tibiae with appressed pile and scales. The tibiae often have numerous, long, speculate spines or bristles. Thorax gibbous and often strongly and conspicuously arched. Abdomen arched and decumbent, or straight, cylindroid and elongate. (Toxophorinae of Hull).
7’ Prothorax short and normal. Macrochaetae if present never exaggerated. Thorax and abdomen not exceptionally arched, gibbous, and decumbent.
7.1 Occiput with dense, rather short erect pile of no great length. Stout, rather flattened and short, robust flies with strongly arched mesonotum and decumbent head and abdomen. Antennae elongate. Three posterior cells.
Toxophora Meigen with six species in the east
7.1’ Occiput with numerous erect, long, spikelike bristles. 4 posterior cells.
Lepidophora Westwood with two species in the east
8 Small, compact flies of 2 to 5 mm in length, in which the third antennal segment is blunt and obtuse at the apex, and bears a short, thornlike spine, concealed or exposed, lying in a recess which may be either lateral and subapical, or dorsal and subapical, or apical and situated between two short protuberances above and below the spine. Anterior margin of oral opening always knife-sharp, the inner walls vertical and the oral cavity deep. Proboscis ling and slender and always longer than the head; palpus likewise slender, usually long. Wings broad at the base and upon the axillary portion. Never more than 2 marginal cells present. Discal cell always much wider apically and first posterior cell widest at the wing margin. Males holoptic and head of male flattened across the top of eyes. Head of female with the front flattened and bearing a transverse groove or fovea over the depressed middle portion. Tibiae and femora with fine pile only; the hairs sometimes stiffened; bristles and spicules absent (Phthirinae of Hull).
8’ Flies not with these characters collectively. (Bombyliinae of Hull).
8.1 Angular veins and stumps of veins present in the discal cell; anterior branch of third vein usually rectangular with stump vein.
Poecilognathus Jaennicke with three species in the east
8.1’ Discal cell without angulated veins and stumps. Anterior branch of third vein always arising gently. Upper genofacial area typically with abundant long hair.
Tmemophlebia with two species in the east
9 Middle of lateral posterior eye margin distinctly indented, but central occiput normal and without enlarged cavity.
Heterostylum Macquart with two species in the east
9’ Lateral posterior eye margin continuous and entire, without indentation. Central occiput likewise normal, with at most a small central depression.
10 First posterior cell open, even if narrowly open.
10’ First posterior cell always closed and usually with a long stalk, rarely closed in the margin.
11 Second antennal segment as long as the first or longer, and both cylindrical, stout, much thickened, and bristly. Marginal cell not usually widened apically. Third segment flat but much widened in the middle, the apex with some long stiff hairs. Three submarginal cells.
Aldrichia Coquillett with two species in the east
11’ Second segment of antenna shorter than the first, usually much shorter; neither segment extensively thickened.
12 Both marginal and first submarginal cells greatly and exceptionally widened in the outer half. Second submarginal cell as wide as long or wider. Three submarginal cells present.
Lordotus gibbus Loew 1863 is the only species in the east
12’ Marginal and submarginal cells usually not widened; only the marginal cell widened or the first submarginal cell or neither, but not both. Second submarginal cell long or short, but longer than wide; usually with 2 submarginal cells; rarely with three submarginal cells.
Sparnopolius confusus Widemann 1824 is the only eastern species
13 First posterior cell closed in the margin, or with a very short stalk. The anterior crossvein enters the discal cell at the basal third, therefore the first basal cell is clearly but not greatly longer than the second basal cell. Both males and females usually with a patch of pale, or silvery hairs or scales on the eye margin opposite antenna.
Parabombylius Williston with three species in the east
13’ First posterior cell closed with a long stalk. The anterior crossvein enters the discal cell at the base, the middle or beyond.
14 First basal and second basal cells of nearly equal length, the first basal cell at most only slightly longer than the second.
14’ First basal cell clearly much longer than the second.
15 Face and oragenal cup well hidden by dense, long pile. Upper anterior intercalary vein long, as long or longer than the anterior crossvein. Anterior branch of third vein often with a spur. Posterior margin of terga usually if not always with rows of long, erect bristles. Pulvilli reduced in length. Head as broad or broader than mesonotum. No transverse groove or depression in front of female.
Anastoechus barbatus Osten Sacken 1877 is only species in the east
15’ Face and oragenal cup with long, but loose, scattered pile. Upper anterior intercalary vein much reduced, shorter than the anterior crossvein. Abdominal pile dense, fine, long, erect plushlike. Anterior branch of third vein without spur. Pulvilli will developed. Head narrower than mesonotum. Female front often with transverse depression. Labellum filiform.
Systoechus Loew with three species in the east
16 Bombylius Linne' with 14 species in the east
16’ Thevenemyia Bigot with three species in the east