428 Forty-sixth Report o.v the State Museum 



apparently commencing not far above the ground and gradually 

 extending upward. When the grubs are numerous, their broad, flat 

 burrows so reticulate and run into one another as effectually to girdle 

 trunks of two to three feet in diameter, when, with the circulation 

 arrested, the death of the tree inevitably follows. No effective remedy 

 against this attack has as yet been found. It is probable, however, 

 that where it has not proceeded too far, protection may be attained in 

 coating the bark with some thick repellant substance (of whioh carbolic 

 acid and Paris green should be components) that would repel egg- 

 deposit or prevent the passage through of the newly-hatched larva. 

 This coating would not need to be applied to the entire trunk, but 

 might be limited to a broad zone of several feet, at and beyond that 

 part where the burrows of the preceding year were mainly run — to be 

 found by removing portions of the bark, which will readily scale off 

 from the deserted older-infested portions. 



A still better remedy, I think, would be the following: Remove the 

 outer bark from the entire infested portion of the tree in the spring 

 (occupied at the time by the larva' or the pup:e) by shaving it down to 

 the inner bark until the first indications of the fresh burrows are dis- 

 closed. A kerosene emulsion of good strength brushed over the shaven 

 surface would kill the insects, after which a coating of some thick sub- 

 stance, as lime and cow- dung, should be applied to prevent the splitting 

 of the sap-wood from exposure to the sun, drying winds or extreme 

 weather. 



That the barking of elms to even a greater extent than the above 

 may safely be resorted to, appears from experiments made in France by 

 M. Roberts, detailed in the Gardeners'' Chronicle and Agricultural 

 Gazette for April 29th, 1848, and quoted by Dr. Packard in his recent 

 report on " Insects Injurious to Forest and Shade Trees" (1890), as 

 follows : 



" The whole of the outer bark was removed from the elm (this may 

 be done conveniently by a scraping-knife shaped like a spoke-shave). 

 This operation caused a great flow of sap in the inner lining of the bark 

 (the liber) and the grubs of the Scolytus beetle were found in almost 

 all cases to perish shortly after. The treatment was applied on a large 

 scale, and the barked trees were found, after examination by the com- 

 missioners at two different periods, to be in more vigorous health than 

 the neighboring ones of which the bark was untouched. More than 

 two thousand elms were thus treated." 



M. Robert has also obtained good results from cutting out strips of 

 the bark of old elms of about two inches wide from the boughs down 

 to the ground. " It was found that where the young bark pressed for- 



