362 



ECONOMIC IMPORTANCE OF ANIMALS 



many fish and much other food, but, as we know, more than com- 

 pensate by the good they do. Large numbers of fish are killed 

 by minks, otters, seals, and other fishing mammals. It was esti- 

 mated that annually $20,000,000 loss to live stock in this country 

 was caused by carnivorous animals, such as wolves, coyotes, and 

 other flesh-eaters. But this amount is rapidly decreasing. 



±£ow the boll weevil gradually advanced over the Cotton Belt, 1892 to 1922. 



Economic Loss from Insects. — The money value of crops, 

 forest trees, stored foods, and other materials destroyed annually 

 by insects is beyond belief. It is estimated that they get one 

 tenth of the country's crops, at the lowest estimate a matter of 

 about 11,000,000,000 yearly. 



Insects which damage Garden and Other Crops. — The grass- 

 hoppers and the larvae of various moths do considerable harm 

 here, especially the '' cabbage worm," the cutworm, which eats all 

 kinds of garden truck, and the corn-ear worm, a pest on corn, 

 cotton, tomatoes, peas, and beans. 



Among the beetles which are found in gardens is the potato 

 beetle, which eats the leaves of the potato plant. This beetle 

 formerly lived upon a wild plant of the same family as the potato, 

 and began to infest potato fields when that crop was introduced in 

 Colorado, evidently preferring cultivated forms to wild forms of 

 this family. 



The one beetle doing by far the greatest harm in this country 



