272 



DIPT ERA. 



and appears like a part of the thorax, reminding one 

 of the cephalothorax of the Arachnida. The ocelh 



are present, but not the 

 compound eyes. The 

 legs are most peculiar 

 in structure, their many 

 joints, hairs, and hooks 

 enabling the creature to 

 cling securely to the 

 hairs of the bat. Wings 

 and halteres, not being 

 needed, have been lost ; 

 the comb-like organs 

 just back of the first pair of legs may be the modified 

 remnants of the wings. This view is supported by 

 the fact that the flies of one genus of the Pupipara 

 (Lipoptena) have wings when young, and live on birds ; 

 afterward they fly to their final destination on quad- 

 rupeds, and then, the wings having become useless, 

 are at last cast off. The whole larval life of the bat- 

 tick is passed within the body of the parent, so that 

 when the insect is born it is covered with a puparium. 



Fig. 221. 



Fig. 222. 



HIPPOBOSCID/E. 



The sheep-tick, Melophagus ovi- 

 nus, Linn. (Fig. 222, with pupa- 

 rium) is parasitic on sheep and 

 lambs. The head and thorax in 

 this insect are small as compared 

 with the enlarged abdomen ; the 

 legs are strong, with claws adapted 

 for clinging. By means of these 



