INSECTS IX RELATION TO HUMAN WEALTH 569 



brown-tailed moth. This kind of work is growing very rapidly. There 

 are now several stations in this country where insects are cultivated on 

 a large scale, to be sent where needed in controlhng injurious insects. 



Fig. 238. The codling moth (Carpocapsa pomonella) 



a, section of apple, showing cavities made by the larva; b, larva, the "worm"' of the 

 apple; c, cocoon: d, pupa: e, adults. The eggs are laid indifferently all about the 

 twigs. This insect does damage estimated at twenty million dollars a year. (About 



natural size) 



Fig. 239. The horse botfly (Gastrophilus eqiii). (Somewhat enlarged) 



The egg, a, is laid on the hair of the horse and is swallowed, together with the larva, b, 

 in the saliva. In the stomach the larvae attach themselves, often causing serious irri- 

 tations and incapacitating the animal for work. The larvae escape from the host with 

 the excrement, and then pupate in the ground, c, pupa; d, adult 



Spraying of orchard trees, shade trees, and crop plants with various 

 kinds of poisonous mixtures is one of the common means used by 

 farmers to control the damage resulting from insect depredations. 



