q. Subcosta and R1 more or less coalescent with the costa; wing pointed at the apex, much longer than the body; antennæ fourteen segmented, not plumose. India. Haasiella Kieff.
qq. Subcosta and radius distinct from the costa.
r. Abdomen petiolate. Dibezzia Kieff.
rr. Abdomen not petiolate.
s. Head semi-globose; hind tarsi unusually elongate in the female; antennæ of the male not plumose. Europe. Macropeza Meigen.
ss. Head not globose, more or less flattened in front; antennæ of the male plumose. Widely distributed. Bezzia Kieff.
t. Fore femora, at least, armed with stout spines below. Subgenus Bezzia Kieff.
tt. Femora unarmed. Subgenus Probezzia Kieff.
ii. Media of the wing simple, and otherwise not as in "i". To this group belong numerous Chironomid genera, none of which are known to be noxious to man.
ff. The costal vein apparently is continued around the hind margin of the wing; radius with at least four branches.