THEIR RELATION TO PLANTS 75 



trunks; but I have never known of any serious injury 

 done by them. 



There are many others among the Tineid families 

 that are borers in herbaceous and shrubby plants and 

 some cause galls or other abnormal swellings in the 

 infested stems; and there are many others that mine 

 or bore in leaves, causing a great variety of disfiguring 

 injury, but rarely anything that threatens the life of 

 the plant itself. Many of these little caterpillars and 

 a few larger species make cases or covers of the most 

 diverse character, and others live in shelters spun by 

 the members of one brood from a single laying of eggs. 

 Some live altogether in silken tubes spun by the cater- 

 pillars, and of these some feed underground on the 

 roots of corn and other plants. Quite a number feed 

 inside of fruits, like the Codling moth of the apple or 

 the berry moth of the grape, and a few get into seeds 

 like the Angoumois grain moth. 



We have, then, among the Lepidoptera, a very large 

 number of feeders on vegetable tissue, that destroy 

 portions of the plant without endangering its life, 

 and a comparatively few that are really dangerous to 

 the existence of the organism attacked, however much 

 it may be injured from an economic standpoint. 



The order Hymenoptera contains a large number 

 of species of very great interest: some of them vitally 

 important to the continuation of plant life, and on the 

 contrary a few that are destructive to it: but it is 

 interesting to note that among the bees which have been 

 shown in the preceding chapter to be among the great- 

 est benefactors of plants, we should also find an element 

 of danger. Plants suffer from "blights," "rusts," 

 "scabs" and a variety of other diseases and, recently, 

 plant pathologists have charged that bees in their 

 visits to flowers engaged in the beneficial work of 



