Entomology. 



75 



stances where the twigs had become detached quite near the node 

 marking the commencement of the year's growth, the bark bad been 

 irregularly eaten for an inch or more in extent. 



While the Orgyia is a serious pest in Albany, it has its years of re- 

 markable abundance and of comparative scarcity. Girdled tips, as 

 above described, have been seen each year since 1883, but by no means 

 corresponding in number to the degree of abundance of the caterpillar. 

 Mv attention had not been drawn to them the present year, until much 



• 



(2 1st of August), many tips of unusual length and with perfectly fresh 

 leaves were collected from beneath a large American elm. Each one 

 had broken at the base of the girdling, which had probably been quite 

 near the node of the year's growth. They were of special interest from 

 their great length, varying from 10 to 18 inches. From the growth 

 they had attained, it was evident that the girdling had not been done 

 in the spring or early summer, but in the late summer after the usual 

 brood had completed its transformations. It was clearly the work of a 

 second brood of the insect, and this was confirmed by my having seen, 

 a few days previously from a house-top, while making observations on 

 the elm leaf beetle, the Orgyia larva about one-half grown. 



A distinct second brood of the Orgyia has not been recorded in 

 Albany, although it is known to be double-brooded in Washington and 

 Philadelphia, and probably in Brooklyn, and has also been observed 

 in Boston. The present year, however, has been an exceptional one in 

 the remarkable abundance, the rapid development, and the injurious- 

 ness of several of our more common insect pests. 



Another interesting feature connected with these tips was the illus- 

 tration they gave of the manner in which woody structure is built up 

 —the sap ascending through the sap-wood, and, alter us assimilation in 

 the leaves, returning through the inner bark and depositing its organ- 

 ized material. The bark above the girdling, in healing m a rough and 

 irregular manner, had swollen out at this point in a bulbous-like en- 

 largement, showing very clearly the arrest and deposit of the returning 

 sap consequent on the absence of its natural channels, and the drying 

 and the death of the decorticated wood below it. In a specimen 

 gathered in which the node of the preceeding year remained attached 

 to the fallen twig, the diameter of the new growth above the bulb was 

 at least twice that of the starved node below. 



This peculiar form of Orgyia attack has not been seen upon the 

 horse chestnut, maple, apple or plum, or any of its other food-plants. 



J. A. LlNTXER. 



Albany, N. Y. 



