THE ECONOMIC IMPORTANCE OF ANIMALS 215 



the substance within the boll. It is estimated that if unchecked 

 this pest would destroy yearly one half of the cotton crop, 

 causing a loss of $250,000,000. Fortunately, the United States 

 Department of Agriculture is at work on the problem, and, while 

 it has not found any way of exterminating the beetle as yet, it has 

 been found that, by planting more hardy varieties of cotton, the 

 crop matures earlier and ripens before the weevils have increased 

 in sufficient numbers to destroy the crop (see page 126). 



The bugs are among our most destructive insects. The most 

 familiar examples of our garden pests are the squash bug ; the 

 chinch bug, which yearly does damage estimated at $20,000,000, by 

 sucking the juice from the leaves of grain; and the plant lice, or 

 aphids. One, living on the grape, yearly destroys immense num- 

 bers of vines in the vineyards of France, Germany, and California. 



Insects which harm Fruit and Forest Trees. - - Great damage is 

 annually done trees by the larvae of moths. Massachusetts has 



Female tussock moth which has 

 just emerged from the cocoon 

 at the left, upon which it has 

 deposited over two hundred 

 eggs. (Photograph by 



Davison.) 



Caterpillar of tussock moth, 

 graph by Davison.) 



(Photo- 



already spent over $3,000,000 in trying to exterminate the imported 

 gypsy moth. The codling moth, which bores into apples and pears, 

 is estimated to ruin yearly $3,000,000 worth of fruit in New York 

 alone, which is by no means the most important apple region of 

 the United States. Among these pests, the most important to 

 the dweller in a large city is the tussock moth, which destroys our 

 shade trees. The caterpillar may easily be recognized by its hairy, 



