9 



twig is inhabited but the laterals as well, and there may thus 

 be several larvie, each in its individual twig, pushing down- 

 ward to the base, in which l)ut one of them can survive. The 

 one that is foremost in this blind race, as it passes below its 

 fellows cuts off their food supply and leaves them to perish in 

 their homes. In some instances larvae have been observed to 

 pass the whole length of water-shoots and for a short distance 

 into the wood of the tree itself. 



The effect on the trees is to destroy the growth of shoots 

 put forth prior to the middle of June. This injury, continued 

 year after year, results in bunches of dead stubs, a clump of 

 which is shown in the colored plate (,11.), drawn from a speci- 

 men cut by me from a tree in one of the parks in Decatur. 

 The short blackened stub to the right shows the work of the 

 larvte two years ago; the longer one to the right of it, with the 

 two blackened laterals, shows the work last year; while the 

 green and brown shoots show the effect on the twigs the pres- 

 ent season. The single small twig at the extreme right, which 

 sprang out from the base of a larger one already affected, was 

 the only one of the cluster that had escaped destruction, it 

 having Ijeen put forth after the beetles had disappeared. By 

 another year this whole group of twigs would have become 

 hollow blackened stubs. Fresh growths being attacked and 

 destroyed in the same manner, the cluster of dead stubs is in- 

 creased year after year. In such a case as that of the unin- 

 jured twig at the extreme right in the colored plate, the larva 

 would continue its work another spring and, passing below the 

 juncture, finish the destruction of the group. 



HABITS OF THE ADULT INSECT. 



Two very striking peculiarities were observed by both Mr. 

 Titus and myself. In the twenty-five years that I have been 

 studying the habits of insects, I do not recall an instance of 

 such seemingly utter disregard for the perpetuation of the 

 species as is exhiljited l)y these beetles. The vicious assaults 

 which they make on each other, regardless of sex, are paralleled 

 only among the Mdididw and some species of spiders. While I 



