XXII] DESCRIPTION AND BIONOMICS 373 



The head is generally flattened and usually fits into an 

 emargination of the thorax. The antennae are apparently one- 

 jointed and are inserted in pits or depressions, situated near 

 the border of the mouth. The maxillary palps ensheath the 

 proboscis, which closely resembles that of Glossina, but never 

 projects in front of the head. The eyes are round or oval, and 

 are widely separated in both sexes ; ocelli may be present or 

 absent. The thorax is flattened, strongly chitinised, and 

 leathery in appearance ; the scutellum is broad and short. 

 The abdomen is unsegmented. The legs are rather short and 

 very strong, broadly separated by the abdomen and end in 

 powerful claws. The wings may be well-developed, rudimen- 

 tary, or entirely absent ; when present the veins are always 

 concentrated towards the anterior margin. The halteres are 

 small or rudimentary. 



The length of the adult insect may vary from about 3 mm. 

 up to ii'5'mm. 



Bionomics. The Hippoboscidae live amongst the fur or 

 feathers of either mammals or birds, and by means of their 

 strong legs and claws are enabled to cling to their hosts. As a 

 result of the adoption of this parasitic mode of life, the wings 

 have gradually become rudimentary and in Melophagus ovinus, 

 the common " sheep-ked," they are entirely wanting. They 

 run about on the surface of their hosts, and even when possessing 

 well- developed wings make little use of them. They feed 

 entirely by sucking the blood of birds and mammals, and 

 except for some special reason, such as the death of the host, 

 rarely leave its body. The bites of Hippoboscidae are not very 

 painful to man, but the sensation produced by their sharp 

 claws hanging to the skin is most unpleasant. However, 

 none of the species, except fortuitously, ever attack man. 



Reproduction. As in the case of Glossina, the female 

 Hippoboscid at certain intervals gives birth to a fully grown 

 larva which at once proceeds to pupate. The body of the 

 larva exhibits practically no trace of segmentation and thus 

 differs from those of the true Muscidae. The female may 

 deposit its larva either amongst the hair of its host (e.g. Melo- 

 phagus) or on the ground (e.g. Lynchia), but precise information 



