PHYLUM ARTHROPODA. INSECTS 



259 



have been introduced from other countries, 

 such as the San Jose scale, European corn 

 borer, cotton boll weevil, Japanese beetle, 

 and Mediterranean fruit fly. Among the 

 sucking insects that may be classified as farm 

 pests are the aphids, scale insects, stink 

 bugs, Hessian fly maggots, and leafhoppers. 

 The chinch bug is especially notorious be- 

 cause of its injuries to corn and small grain. 

 Chewing insects of importance include wire- 

 worms, white grubs, the European corn 

 borer, flat-headed borers, bark borers, alfalfa 

 weevils, corn-ear worms, and cotton boll 

 weevils. Stored grain is destroyed in large 

 quantities by beetles of various kinds, es- 



pecially by weevils and by caterpillars of 

 moths. 



Insects injurious to 

 domestic animals 



Domestic animals are often seriously in- 

 jured by insects. Biting lice, such as the 

 chicken louse (Fig. 158) may feed on 

 feathers and cause loss of flesh by their con- 

 stant irritation. Sucking lice are even more 

 injurious. Among the flics, the horn fly is a 

 bloodsucking species and a serious pest of 

 cattle. The larvae of the horse botflies (Fig. 

 158) may cause series disturbances to the 



Larva hatches, migrates through body 

 to skin of back 



Adult fly 

 emerges, 

 lays eggs 

 on hairs 

 of cow 



Cattle grub 

 (Diptero) 



Pupates in 

 ground 



Larva and air 

 hole in skin 



Sheep "tick" 

 (Diptero) 



Larva hatches, 

 migrates to 

 stomach 



Horse botfly 

 (Diptero) 



Larva "bot" 

 in stomach 



/ 



Pupates in ground 



Adult botfly emerges, lays eggs 

 on hairs of horse 



Chicken louse (Mollophago) 



Figure 158. Insects injurious to domestic animals. Each year livestock pests cost this country 

 about $500,000,000. Figures of insects are not drawn to scale. 



