Diptera 



267 



give off from three to five very slender nervures which reach the 

 vifing-margin. The hind-body is short, tapering, and bent down- 

 wards ; six or seven segments are visible. The larvse mostly live 

 as parasites on snails and insects. 



The three concluding families of the Diptera are degraded, 

 parasitic flies in which development up to the pupal stage is com- 

 pleted v/ithin tlie mother's body ; they were therefore formerly 

 classed as a distinct sub-order (Pupipara;. The jaws are much less 

 modified than in Diptera generally (hence the name Eproboscidea 

 sometimes applied to the group) ; parts of the second maxillse are 

 recognisable as paired lobes at the base of the sucker (155). 



Hippoboscidae. — The Hifpobusdda are flies of flattened shape 

 with the head comparatively small, sometimes partly sunken in the 

 thorax. The feelers, which have apparently but a single segment, 

 are hidden in cavities ^ 



near the mouth. The "^ 1-' -^ 



legs are short and 

 strong with broad, flat 

 thighs; the short, 

 wide feet have large 

 claws. Wings when 

 present have a neura- ,'' 

 tion akin to that of 

 the Muscaria ; in some 

 genera (as Melophagus 

 — the well-known 

 "Sheep-tick"— (fig. 

 165) they are want- 

 ing. These insects 

 live parasitically on 

 mammals and birds ; 

 the Horse " Forest- 



FiG. 14S. — Horse " Forest-fly" (H ippobosca equina^ 

 Linn.), Europe. Magnified ^ times. From 

 Osborn (after Packard), Bull. 5 (n.s.), Div. 

 Ent. U.S. Dept. Agr. 



fly" (Hippoboscj equina') (fig. 148) is a typical example of the 

 family. 



Braulidae. — The BrauHJce or '-Bee-lice" are minute wingless 

 insects allied to the Hipp'fboscids, but distinguished by the short 

 sucker, the second maxillae being clearly paired, as well as by the 

 absence of both simple and compound eyes. The feelers, sunk in 

 cavities of the head, are clearly three-segmented with a feathered 

 bristle. The thorax is broad, and there is no scutellum. Wings 

 and balancers are alike absent. The legs are short, with thick 

 thighs, bent shins, and five-segmented feet; the terminal foot- 

 segment is very Ijroad and beats instead of claws, comb-like rows 

 of spines. The family comprises but a single genus (^BruuLt) which 

 lives parastically on Bees. 



Nycteribiidae. — The NijctaribUda or Bat-parasites are the most 



