CLASSIFICATION OF INSECTS 329 



A A. Adults usually ectoparasitic upon warm-blooded vertebrates; abdomen 



indistinctly segmented. Larvae born when about to pupate. PUPIPARA 



B. Winged or wingless flies : eyes faceted ; palpi forming a sheath for 



the proboscis ; veins of the wing, when present, crowded anteriorly, the 



weaker veins running obliquely across the wing. Parasitic upon birds 



and mammals. House-flies HIPPOBOSCIDAE 



BB. Winged or wingless : when present the wings are pubescent, with 



parallel veins and outer cross-veins ; eyes usually unfaceted ; ocelli 



wanting; antennae 2 -jointed ; palpi broad, not forming a sheath for 



the proboscis. Usually parasitic upon bats .... STREBLIDAE 



C. Wingless ; halteres present ; eyes vestigial ; head folding back on 



the dorsum of the thorax. Small, spiderlike flies ; parasitic upon 



bats. Bat-ticks NVCTERIBIIDAE 



CC. Wingless ; halteres absent ; eyes vestigial ; last joint of the tarsi 

 with a pair of comblike appendages. Parasitic upon the honey- 

 bee. Bee-louse BRAULIDAE 



