RELATION TO OTHER ANIMALS 



181 



its eggs on the hair of the animal it infests, and here 

 also further development is dependent upon the in- 

 troduction of the young larva into the mouth. But 

 there the resemblance ceases, for the young larva, in- 

 stead of permitting itself to be carried to the stomach, 

 attaches itself to the walls of the oesophagus and bores 

 its way through into the muscular tissue, continuing on 

 until it reaches the desired position beneath the skin. 



FIG. 81. The ox bot, Hypoderma lineata: a, eggs attached to hair; 

 b, fly; c, larva. 



As with the horse, the well-cared-for dairy animal 

 rarely suffers from bots; the eggs are so conspicuous 

 that they readily attract attention, and removal is 

 easy. If any do escape and bot-swellings are noticed, 

 they should be lanced and the contained larva removed. 

 Cattle on the range or beef cattle in pasture suffer much 

 more, because they are less or not at all looked after, 

 and the bots are not suspected until the ulcerating 

 sores attract attention. 



A still more highly specialized type is represented 

 by the "louse flies," sometimes separated under the 



