71 



Damage usually becomes manifest some time in July in the more 

 northern States, and southward earlier, in June. In cases of severe 

 attack the leaves turn brown as if scorched by fire. Injurious attack 

 is not often brought to the notice of economic entomologists, which is 

 rather remarkable considering that the locust is of great value as a 

 timber tree, for posts, etc., though of less importance as a shade tree 

 than elm, oak, maple, and others with which everyone is familiar. 

 Thus it happens that although year after year this insect has done 

 much harm to the locust, where this tree is of value, comparatively 

 little has been published concerning the insect's ravages, its life history 

 and habits. 



Like many other insect pests, it is subject to considerable fluctuation 

 in numbers, in some years being quite destructive while in others it 

 attracts little notice. It is nearly always more or less troublesome to 

 the locusts in Maryland, Virginia, and the District of Columbia, and in 

 recent years has been reported as more or less destructive in neighbor- 

 ing States. Injur}^ has been reported in West Virginia from 1890 to 



1897, in New York and New Jersey in 1896, in Maryland from 1896 to 

 1899, in Ohio and Kentucky in 1897, in Pennsylvania and Kentucky in 



1898. These reports probably do not b}^ any means sum up the entire 

 area infested during the past ten years. In 1898 this beetle did more 

 than usual damage over a considerable portion of this territory. 



In most seasons this beetle does little more harm to the locust than 

 to mar its beauty as a shade tree, but in j^ears of its greatest abun- 

 dance it is probable that trees are so badly weakened by the combined 

 ravages of this and other leaf -miners that the result is practically the 

 same as that of defoliation; the trees are so weakened that they readily 

 succumb to disease, to unfavorable atmospheric conditions, and to the 

 destructive work of different species of borers, such as the painted 

 locust borer {Cyllene robinlx Forst.), a species which is of still more 

 importance as an enemy of this tree. 



In the vicinity of the District of Columbia the damage effected by 

 this leaf -miner is frequently as bad as reported elsewhere, and we 

 have observed locust groves where the injury was almost entirely due 

 to the work of the beetle, while in others the Tineid leaf-miners were 

 more numerous. As a rule, however, this locust beetle is more 

 abundant about Washington than all of the leaf -mining Tineidaj and 

 other locust pests taken together, and its importance in economic 

 entomology is deserving of a more detailed consideration than has 

 hitherto been given to the public. 



Injury is usually most severe to young trees and to such as have 

 low, vigorous branches, and to others growing on the edges of sunny 

 lawns and in similar locations. There are, however, some striking 

 exceptions. In many localities such plants suffer greatly 3"ear after 

 year. Taller trees, on the contrarv, are much less subject to injury. 



