— >74 — 



for friendly crilicism, and whether or not it shall be completed finally, 

 depends upon what is left of it after you have done. A few weeks since 

 it was my pleasure to revisit the "old homestead" in Oswego Co., N" Y., 

 and to tramp for a few days over hills and swamps dwelling uj)on the 

 memories of boyhood days and endeavoring to capture a few insects for 

 mementos and for my collection. In getting a few I was successful. 

 One of interest among this number is the Cossus who.se larva and pupa 

 are the subjects of the following notes. 



The discovery of the borer was accidental; passing along the bolder 

 of a brook I came upon some alder.s, A. iricana, which had been drawn 

 out root and branch upon dry ground: one stem had been broken off 

 near the root disclosing the cyhndrical gallery of an insect borer very 

 different from those made by a beede larva common in the same stems. 

 An examination brought to light numerous examples of a Cossus larva 

 in the roots and stems of the alders in the vicinity. The flicts in its 

 history were partially made out. 



Larvce of two distinct sizes were about equally abundant; the larger 

 ones at the time, June 29th, were moulting. As the imagos, probably, 

 had escaped it seems pretty certain that the preparatory stage lasts three 

 years, i.e., the smaller larvae were one year old, the larger two and these 

 transform next May or June. Several pupa-shells (all broken) were 

 found in the openings in the bark, and one pupa, which was dead but 

 in perfect conditi(.)n. The larva, it seems bores principally in the roots 

 until the second year, when it begins to work upward in the trunk, and 

 before pupating in the spring of the third year, bores out to the surface a 

 few inches above the ground. The pupa-cell, a mere enlargement of the 

 burrow a little below the external opening, is not stopped or plugged 

 with chips as is the case in the cell of C. Centcrmsis; none were found 

 in the roots and no evidence was obtained that the larva bores in the 

 trunks save towards the end of its period, when it moves upward to pre- 

 pare a way for the moth to escape where it is out of the way of danger 

 of water, as the alder grows in wet places. This moth escapes as others 

 of its kind do, by the pupa worming its way out of the cell so that part 

 of its body protrudes from the tree when the moth emerges leaving the 

 skin in the opening. 



I will describe the larger of the larvx> and compare the smaller one 

 as it may differ. 



Length 1.5 to 1.8 inches. Subcylindrical, tapering very slighlly at extremities, 

 slender, width of body .25 of an inch. Length of smaller ones .8 inch. The head is 

 light yellowish brown above, black about the mouth parts, hemispherical, smooth, 

 or slightly roughened, with a few dark dots from which arise dark hairs, usually 



