Packard.] ESTSECTS OF THE EOREST. 239 



eluding many spiders, mites and thousand-legs which con- 

 gregate in these retreats. 



Now turning our steps towards tlie hard wood growths we 

 shall find that the oak harbors a great number of insect 

 inhabitants. "We could enumerate from thirty to forty dif- 

 ferent kinds injurious to the oak in tlie northern states. 

 The walnut is infested by a still larger number, fully seventy' 

 species. The elm struggles against the attacks of about 

 twenty-five diflTerent kinds, while the locust and maple have 

 a less number of species specially injurious. 



The oak suffers from the attacks of numerous gall-flies, 

 which, not content with deforming the branches and leaves 

 W'ith unsightly tumoi's, sting even the roots, producing excres- 

 cences like ground nuts on the smaller rootlets. These little 

 root gall-flies are wingless and look lilie little black ants. 

 They are, strange to sa}^, found only early in winter on the 

 snow. They are rare and more curious than destructive. 



If one will examine a pile of freshly cut red oak wood he 

 will find the sticks of cord wood pretty thoroughlj^ riddled 

 with large holes and tunnels, nearly half an inch in diame- 

 ter. This is the work of a large fleshy caterpillar, the young 

 of the Cossus. It is the most destructive of all the insects 

 feeding upon the oak, as after the worm is hatclied, — and 

 there are a good many of thom, since tlie female lays about 

 three hundred eggs, — they bore directly into the heart of 

 the tree, leaving a passage for the rain and moisture, which 

 aid iu the work of destruction. The caterpillar is thought 

 to be three years in attaining its full size, its life being an 

 unusually long one, as few caterpillars are known to live 

 longer than one season. It also infests the locust tree. 



If a favorite shade tree has been attacked, the best way to 

 prevent farther mischief is to soap the trunk in June and 

 July, and thus prevent the moth from depositing its eggs, or 

 after the holes appear to plug them up in order to keep the 

 water out. 



15 



