i. Proboscis scarcely extending beyond the palpi; front of the female wide; much wider below than above. S. W. States. Apatolestes Will.
ii. Proboscis extending beyond the palpi.
j. Wing with cell M3 closed. Tropic America. (= Diclisa) Scione Wlk.
jj. Cell M3 open; ocelli present or absent. Two or three eastern species; many south and west. Pangonia Rdi.
ff. Third segment of the antenna with five divisions; ocelli present.
g. First and second segments of the antenna short, the second only half as long as the first, three western species. Silvius Rdi.
gg. First and second segments of the antenna long, the second distinctly over half as long as the first. Deer flies. Many species, widely distributed. Chrysops Meig.
ee. Hind tibia without spurs; ocelli absent.
f. Third segment of antenna with four divisions, no tooth or angulation; wings marked with rings and circles of darker coloring; front of the female very wide. Widely distributed. H. americana, H. punctulata. Hæmatopota Meig.
ff. Third segment of the antenna with five divisions ([fig. 161b]).