752 



CLASS IV. INSECTA. 



Most species have larvae parasitic in other insects. tS 1 . carnaria is a common 

 British form which resembles the Blow-fly. 



Fam. (ill. Muscidae. Anteiinal bristle feathered. This family includes 

 the house-fly, blue-bottle, etc. They lay their eggs in dead flesh or dung. 

 The common house-fly Musca domestica usually deposits its eggs in 

 stable manure, the larvae live on their surroundings for less than a week 

 and then pupate, and the imago emerges about a fortnight after oviposi- 

 tion (Hewitt, Q.J.M.S., 51, 1907, p. 395). Two common species of blow- 

 fly are found in Britain, Calliphora vomitoria and C. erythrocephala. 

 Glossina includes the dreaded Tsetse-flies of Africa (Fig. 479). 



Fam. 70. Oestridae. Large, hairy flies with very short antennae 



bearing a segmented bristle. 

 Posterior part of wing with few 

 nervures. Mouth parts often 

 aborted. The larvae of the Bot- 

 flies live in Vertebrates and for 

 the most part in Mammals. The 

 family is a small one, but there 

 are some ten British species, 

 which attack cattle and deer. 

 OastropMlus equi lays its eggs on 

 the hair of horses. On hatching 

 they set up an irritation which 

 causes the horse to lick the place, 

 and the larvae being thus 



swallowed, come to rest in the 

 FIG. 480. Gastrophilus eqiu (after P. Brauer). ,, ,. , - , 



a larva ; female. stomach, to the walls ot which 



they attach themselves until 



ready to pupate, when they pass out with the excreta. Hypoderma lineata 

 Andbovislay eggs on the legs of cattle. Later, the larvae are found caus- 

 ing the " warbles " or tumours under the skin of the back. They are 

 probably licked off the legs and swallowed, and burrowing through 

 the gut-walls, reach their position under the skin, but, at present, there 

 is some doubt as to the route by which they reach their final destination. 

 When full-grown they emerge from the warbles, fall to the ground, and 

 pupate therein. Oestrus ovis places its larvae it is viviparous in the 

 nostrils of sheep, whence they wander into adjacent cavities. 



Group 5. PUPIPAEA. 



A iji'on ji degraded by parasitism. The members for the most part suck 

 blood. They are viviparous, producing larvae which immediately pupate. 



Fam. 71. Hippoboscidae. Wings large, small or absent. The body 

 and legs are flattened. The singly-segmented antennae are hidden and 



-FIG. 481. Hi/rpobosca equinu. 



FIG. 482. Melo'phagus ovinns. 



