Two European species of this genus have been accused of blood sucking habits, but the record seems to have been based upon error in observation.
ee. With another combination of characters. Stratiomyiidæ, Cyrtidæ, etc.
cc. Empodium bristlelike or absent.
d. Antennæ apparently two segmented, with three-segmented arista, wings (rarely wanting) with several stout veins anteriorly, the weaker ones running obliquely across the wing ([fig. 163h]); small, quick running, bristly, humpbacked flies. Several genera; Aphiochæta, Phora, Trineura, etc. Phoridæ
dd. Flies with other characters.
e. No frontal lunule above the base of the antennæ; both R4 and R5 often present; third segment of the antenna often with a terminal bristle. Asilidæ, Mydaidæ, Apioceridæ, Therevidæ, Scenopinidæ, Bombyliidæ, Empididæ, Dolichopodidæ, Lonchopteridæ.
ee. A frontal lunule above the base of the antennæ; third segment of the antenna always simple, i.e., not ringed, usually with a dorsal arista; R4 and R5 coalesced into a simple vein.
f. A spurious vein or fold between the radius and the media, rarely absent; the cell R4+5 closed at the apex by vein M1; few or no bristles on the body, none on the head; flies frequently with yellow markings. Eristalis ([fig. 163i]), Helophilus, and many other genera. Syrphidæ
ff. No spurious vein present.
g. Body without bristles; proboscis elongate and slender, often folding; front of both male and female broad. Conopidæ