\ 



137 



by the sneezing of the sheep. They burrow into the 

 ground, where the pupal stage is passed (Fig. 147). This 

 occupies some 4 to 6 weeks. 



Control. When the sheep bot occurs in numbers, 

 various plans are adopted to prevent the access of the 

 adult fly or to dislodge the grub. The latter is considered 

 the most useful measure to take with this insect. For this 

 purpose, the animal may be caused to sniff a small quantity 

 of dry lime, and the sneezing thus induced will dislodge the 

 maggot if it has not become too well established. The 

 use of a feather dipped in turpentine will cause the 

 detachment of maggots in the lower part of the nasal 

 passages; but when they have become fixed in the 

 sinus between the bones of the head, to loosen them 

 is extremely difficult, if not impossible. The use of 

 some substance, on the nose of the sheep, which is 

 disagreeable to the fly may prevent egg-laying to a certain 

 extent, but cannot be depended on entirely, especially 

 where these insects are abundant. Tar has been used for 

 this purpose. 



The horse bot (Gastrophilus eqai, Fabr.) differs in 

 several particulars in its life-history from the preceding. 

 The eggs are not hatched within the body of the female 

 fly ; they are deposited on the long hairs of the 

 forelegs and chest of the horse, where they hatch. 

 The maggots are removed by the tougue of the horse in 

 licking itself, and carried to the mouth and swallowed. 

 The larvae attach themselves to the lining of the stomach 

 of the horse, where they remain for several months. 

 When fully grown they loosen their hold and are passed out 

 of the body of the host with the dung. The pupal stage 

 is passed in the ground like that of the sheep bot. 



The bot of cattle is known as the warble fly. 

 This is Hypoderma lineata, Will., or H. bovis, de G. The 

 adult female deposits its eggs on the hair of the shoulders, 

 neck, etc., of the cattle, from which places eggs or newly 

 hatched larvae are licked off and swallowed by the host. 

 The maggots penetrate the walls of the alimentary 

 tract and finally reach the subcutaneous tissues of the 

 back, where they remain for some months, throughout the 

 pupal stage. When fully grown, the maggots penetrate 

 the skin of the host and fall to the ground, and then the 

 pupal stage is passed through in a similar way to that of 

 the bots of the sheep and horse. 



