374 HIPPOBOSCIDAE [CH. 



on this subject is lacking. After a variable incubation period 

 the pupa, which is of the usual Cyclorrhaphous type, splits off 

 a cap at the anterior end and the perfect insect emerges from 

 the circular aperture thus formed. 



HippohoscidcB and disease. Up to the present no truly 

 pathogenic organisms have been shewn to be carried by Hippo- 

 boscidae, but two species of Hippohosca are said to transmit 

 Trypanosoma theileri occurring in cattle in the Transvaal, and 

 three species of Lynchia have been shewn to carry the pigeon 

 halteridium, Hcemoproteus columhce. The insects, therefore, 

 are of little importance from the point of view of disease- 

 carriers, but some of them are of economic interest because of 

 the harm they do to domestic animals, through mere irritation. 



Classification. The Hippoboscidae may be divided into 

 thirteen genera as follows : 



Synopsis of the genera of Hippoboscidce after Speiser'^. 



A. Wings ivell developed and functional. 



/Claws with the usual two points (heel and tip) ; parasitic on mammals = 2 

 \ Claws with three teeth ; parasitic on birds . . . . . . . . =3 



rHead of normal form, not broadly impinging on thorax, freely movable ; 

 J ocelli absent ; wings always present . . . . = Hippohosca. 



j Head flat, broadly impinging on thorax ; ocelli present ; wings sometimes 

 L becoming detached (in female) leaving only a shied =Dipoptena. 



f Ocelli present . . . . . . . . . . . . . . . . =4 



\ Ocelli wanting (no anal cell) .. .. .. .. .. .. =5 



/ Anal cell present . . . . . . . . . . . . . . =6 



^ \ Anal cell absent .. .. .. .. .. .. =Ornithophila. 



r Wings of a peculiarly pointed form (vide Fig. 85), the tip rounded = Lynchia. 



5 -( Wings of the ordinary form but less expanded than in Ornithomyia, with 



I broadly rounded tip . . . . . . . . . . =Olfersia. 



C Third longitudinal vein not elbowed at the anterior transverse vein 

 ^ J = Ornithomyia. 



i Third longitudinal vein abruptly bent forwards at the level of the anterior 

 t transverse vein =Ornithasca. 



B. Wings rudimentary or wanting. 



J Wings present, but rudimentary and functionless ; halteres present =2 

 \ Wings and halteres absent .. .. .. .. =Melophagus. 



1 Modified from Alcock's Entomology for Medical Officers, p. 187. 



