REPORT OF THE STATE ENTOMOLOGIST 10,12 65 



to the middle of August. Observations at Bronxville on July ioth 

 showed numerous dead leaves and tips of branches upon affected 

 trees. The beetles were then just beginning to enter the bark. On 

 August 5th a number of beetles were still working in the leaf stem, 

 others were entering the bark and some had evidently become well 

 established. The beetles bore the young twigs and burrow in the 

 terminal buds and green nuts, evidently for food, and in this man- 

 ner frequently cause the wilting of leaves and the death of twigs. 

 Later they attack the bark of the trunk and the larger branches, 

 each female making a vertical gallery an inch or more in length, 

 along the sides of which she deposits in small notches, 20 to 40 or 

 50 eggs. These galleries of the adults are usually very regularly 

 placed, their position apparently being determined in large measure 

 by the long cracks in the rougher bark of the trees. The eggs soon 

 hatch and the grubs work in the tissues, at first at nearly right 

 angles to the primary galleries and later the borers turn in either 

 direction rill they run nearly parallel with the wood and produce a 

 rather characteristic fan-shaped series of galleries. The burrows 

 of the grubs or larvae rarely cross each other. On October 1st 

 most of the larval galleries observed were from one-half to three- 

 quarters of an inch long and the grubs about one quarter grown. 

 They winter in a partly grown condition, transform to pupae the 

 last of May and the beetles begin to appear about a month later. 

 There is no evidence to show that more than one generation occurs 

 in New 'York State, at least. 



Experimental work. The following field work was conducted 

 at Bronxville in cooperation with Mr J. James de Vyver of Mount 

 Vernon. 



Bar enrol. A 10 per cent solution of this proprietary material 

 was applied July 12th to certain hickory trees which were examined 

 August 5th. It was then evident that this compound had a dis- 

 tinct hardening effect upon the outer bark of the tree though there 

 was no penetration by the beetles, a fact confirmed by subsequent 

 observations October 1st. An examination of a few burrows made 

 by the beetles prior to the application showed that the discolora- 

 tion of the inner bark was confined to the immediate vicinity of 

 the galleries and occurred to an almost equal extent on untreated 

 trees. The brown tissues in the latter instance extended to within 

 about an inch of where living grubs were working. Another tree 

 treated with a 50 per cent solution of this material was examined 

 August 5th and it was seen that the application had destroyed the 

 borers. 



