ll. Empodium short, scarcely reaching the middle of the claws, or vestigial. m. R-m crossvein wanting. n. Palpi four segmented; inferior fork of the media obliterated at the base. Australia. _Leptoconops_ Skuse nn. Palpi three-segmented. o. Legs spinulose, tarsal claws of the female with a basal tooth or strong bristle, those of the male unequal, the anterior with a long sinuous tooth, the posterior with a short arcuate tooth. Italy. MYCTEROTYPUS Noé oo. Legs unarmed; no crossvein between the branches of the radius (fig. 163e). New Mexico. TERSESTHES Townsend mm. R-m crossvein present. n. Fore femora very much swollen, armed with spines below, fore tibia arcuate and applied closely to the inferior margin of the femur. o. R_{2+3} present, therefore cell R_1 and R_2 both present; wing usually fasciate. United States _Heteromyia_ Say. oo. R_{2+3} not distinct from R_{4+5}, hence cell R_3 obliterated. South America _Pachyleptus_ Arrib. (Walker) nn. Fore femur not distinctly swollen. o. R_{2+3} present therefore cells R_1 and R_3 both present, or if not, then the branches of the radius more or less coalescent, obliterating the cells. p. At least the tip of the wing with erect setulæ; tip of R_{4+5} scarcely attaining the middle of the wing, empodium rather indistinct, not reaching the middle of the claws, the claws not toothed, equal, with long basal bristle; legs without stout setæ. Widely distributed. CULICOIDES Latr. HÆMATOMYIDIUM and OECACTA are probable synonyms of this.