INSECTS. 





Fig. 250 



Horse bot-fj ophi- 



lus eq<ii) au<l larva. 



with spotted wings, and is well shown in our cut. The adults live bu 

 short time, and never take any food. The whole energies of the female 

 are devoted to obtaining an opportunity to lay her eggs in the proper place. 

 In the choice of this the different species 

 affecting the horse vary somewhat, that fig- 

 ured preferring the region about the knees 

 easily reached by the lips of the horse, while 

 a closely allied form deposits them upon the 

 lips themselves. Each egg is deposited singly. 

 and is fastened by a sticky secretion to one of 

 the hairs. 



In this choice of a position for the eggs 

 there is a due regard, for the life of the larva to be hatched from these 

 depends upon their being placed where they can be taken into the mouth 

 of the horse. The larvae escape from the egg in a few days, and when 

 the horse is nipping the place where they are laid, they find their way into 

 the mouth and thence to the stomach. Here they fasten themselves to the 

 lining walls by means of the little hooks shown at the upper end of the 

 left-hand cut of Figure 250. The result is that they produce sores in 

 the stomach, and. when there are many present, the resulting pain aim 

 drives the animals frantic, and the inflammation ensuing may result in 

 death. 



When full-QTOwn the larvae loose themselves from the walls of the 

 stomach and pass into the intestines along with the food, and are then 

 carried out with the excrement. They now burrow into the earth, 

 pupate, and at length emerge as the perfect fly with which we started. 

 The bot-fly which lays its eggs on the lips of the horse differs from 

 the form just de- 

 scribed in that the 

 larvae burrow into 

 the wall of the in- 

 testine instead of 

 the stomach. 



The bot-flies of 

 cattle differ consid- 

 erably in their hab- 

 its from those of 

 the horse. The 

 eggs are laid as 

 before upon the hair or skin of ruminants, especially in the neigh 

 of the neck, shoulders, and groin. The larva' on hatching burrow 



Fig. 251. —Cattle bot-fly (Hypoderma bovis), larva and pupa, 





