DIPTERA. 489 



where they remain, and having no further use for their 

 wings, they lose them. 



Family NYCTERIBIID^E (Nyc-ter-i-bi'i-dae). 

 The Bat-ticks. 



The bat-ticks are wingless parasites of bats. The body 

 is depressed ; the head is small and folded back into a groove 

 on the dorsum of the thorax. The compound eyes are 

 wanting; the ocelli are present or wanting. The legs are 

 long, and the tarsal claws of ordinary form. Although 

 wingless the halteres are present. 



The mode of reproduction is similar to that of the 

 Hippoboscidae. 



Family BRAULID.E (Brau'li-dae). 



The Bee-louse. 



This is a minute insect, one-sixteenth of an inch in 

 length, which is parasitic upon the Honey- 

 bee (Fig. 597). It is found clinging to the 

 thorax of queens and drones. It is wing- 

 less, and also lacks halteres. The head is 

 large, but lacks both compound eyes and 

 ocelli. The legs are comparatively short ; 

 the last segment of the tarsus is furnished with a pair of 

 comb-like appendages. Only a single species is known ; 

 this is Braula cceca (Brau'la cae'ca). Its mode of reproduc- 

 tion is similar to that of the Hippoboscidae. 



