348 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 



killed outright, and in others the wood is generally reduced in value 

 for commercial purposes. 



So far as known, this species confines itself to the black or yellow 

 locust. The borer is an elongate, compact, yellowish-white grub or 

 larva furnished with three pairs of minute legs (fig. 22, a). Its 

 first work is done in the inner bark, where it destroys a portion of the 

 vital tissues. Later it enters the wood to feed and pupate. It is 

 here that its most destructive work is done, either by so honeycombing 

 the wood as to cause the death of branches or small trees or by 

 injuring the w r ood for commercial purposes (fig. 22). The egg from 

 which the borer is hatched is deposited by the adult female in a 

 crevice of bark on the trunk or a branch, between the middle of 

 August and the middle of October. The larva passes the winter in 

 the bark, where it lies dormant in a hibernating cell of its own 

 construction. In the spring (usually about the second week in April 

 in the vicinity of Washington) activity commences again and the 

 borer leaves the hibernating cell to feed on the inner bark and outer 

 wood. In from two weeks to a month it enters the wood, where 

 it continues to feed and later changes successively to pupa and adult 

 (fig. 22, b). Adults begin emerging from the trees in August and 

 continue emerging till the last of September, the principal period of 

 emergence being the last half of August and first half of September. 

 The adult is an elongate beetle, the ground color of which is black, 

 with numerous cross-bands of yellow. Within a few hours after 

 emergence copulation takes place and the females begin depositing 

 eggs. There is but one generation a year. 



The adults are usually common, feeding on the flowers of goldenrod 

 while this plant is in bloom. 



When infested trees are so badly damaged as to be worthless they 

 should be cut down in May and June and burned to kill the broods 

 of larvae. At this time all such trees can be easily recognized by the 

 boring dust which is thrown out by the larvas and lodges in forks of 

 trees, in crevices of bark, and on the ground underneath. They can 

 also be recognized by the fading leaves, broken branches, etc. This 

 work should be completed by the time the flowers have all fallen from 

 the trees, or before the earliest varieties of goldenrod begin to show 

 evidences of flowering. 



Hibernating larvaB may be killed by spraying the trunks and 

 branches with a strong solution of kerosene emulsion. This method 

 is specially recommended for the protection of small plantations, 

 groves, or shade trees. The work should be done in the fall or winter, 

 not earlier than November 1 and not later than April 1. 



Great care should be exercised as to the time of year when locust 

 trees are cut for any purpose in order that the hibernating borers may 

 be destroyed. Except for the purpose of destroying the borers in the 



