34 



PRACTICAL ZOOLOGY 



FIG. 17. Chinch bugs on 

 a corn plant. (Photo by 

 O'Kane.) 



eggs burrow into the worm and finally kill it. 



eminent bulletins of the insects that 

 are destructive to field crops, such 

 as the army worm and the chinch 

 bug. The army worm (Fig. 15, B) 

 is a black and yellow striped cater- 

 pillar about one and one half or two 

 inches long when full-grown. It is 

 the larval stage (caterpillar) of an in- 

 conspicuous dull-brown moth (Fig. 

 15, A). These caterpillars may 

 occur anywhere east of the Rocky 

 Mountains and sometimes become 

 so abundant that they must migrate 

 in search of food. At such times 

 they crawl along in vast armies 

 feeding, usually at night, upon the 

 leaves and stalks of grains and 

 grasses, the heads of which they 

 generally cut off. The crops over 

 large areas are in this way totally 

 destroyed, with a tremendous loss to 

 the farmer and indirectly to the 

 final purchaser of the food manu- 

 factured from grain. 



METHODS OF CONTROL. Fortu- 

 nately army worms are killed in 

 enormous numbers by their natural 

 enemies or they would soon make 

 the world uninhabitable. The ta- 

 china flies (Fig. 47, B) are their 

 worst enemies. These little insects 

 lay their eggs on the body of the 

 army worm (Fig. 47, C) and the 

 maggots which hatch from these 



