g. Pronotum produced caudad over the scutellum, with a high mesal tuberculate ridge ([fig. 19e]). A. cristatus. N. Y. to Cal. and south. Arilus Hahn.
gg. Caudal lobe of the pronotum six sided, neither elevated nor produced caudad. H. americanus, Southwest; also several W. I. and Mexican genera. Harpactor
DIPTERA (Mosquitoes, Midges, Flies)
a. Integument leathery, abdominal segments indistinct; wings often wanting; parasitic forms. PUPIPARA
b. Head folding back on the dorsum of the thorax; wingless flies parasitic on bats. Genus Nycteribia. Nycteribiidæ
bb. Head not folding back upon the dorsum of the thorax; flies either winged or wingless; parasitic on birds and on bats and other mammals.
c. Antennæ reduced, wings when present, with distinct parallel veins and outer crossveins; claws simple; palpi leaf-like, projecting in front of the head. Flies chiefly found on bats. Several genera occur in North America. Streblidæ