624 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
The discovery of the borer was accidental. Passing along the border of a brook, 
came upon some aiders, .1. Inoana, which had been drawn oat root and branch upon 
iir\ -round; one stria had been broken off near the root, disclosing the cylindrical 
galh-ry ai' an insect borer very different from those made by a beetle larva common 
in the same steins. An examination brought to Light numerous exainplesof a Cossus 
lanra in the roots and Stems of the alders in the vicinity. The- tacts in its history 
were partially made out. 
Larva- of two distinct sizes were about equally abundant ; the larger ones at the 
time, Jnne39, were molting. 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 condition. 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. centerensis ; 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 prepare 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 worm- 
ing 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 larva& and compare the smalter one as it may 
differ. 
Length, 1.5 to 1.8 inches. Subcylindrical, tapering very slightly at extremities, 
slender, width of body .25 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 worn 
off the vertex of the larger examples. The second ring is smooth, lighter colored 
than the head ; above the spiracle on either side there are three black spots situated 
at the corners of a right-angled triangle; the upper one at the right angle bears a 
coarse brown hair, the other two have finer, lighter-colored hairs; the top of the third 
ring is likewise smooth and brownish ; the remaining body surface except the yellow- 
ish piliferous spots and top of ring 13 is white ; the longer hairs on the posterior rings 
are black. The body rings are strongly folded transversely ; the yellowish dorsal 
spots bear brownish hairs; the anterior larger pair are situated rather near together 
on the broadest transverse fold ; the smaller posterior pair are situated on a narrower 
fold and much farther from the slight dorsal furrow. The stigmata are broadly 
elliptical, the rings narrow, black scarcely raised above the surface, the color within 
the ring light brown. The legs are yellowish, hooks black ; the prop legs with very 
many booklets. 
The pupa is slender, length 1.6 inches, width of thorax .33 inch, but slightly curved 
and of unusually uniform diameter, smooth, under a lens transversely striate, the 
three anterior rings black, shagreened ; on the prothorax there are two conical pro- 
tuberances which in profile under a strong lens prove to be double-pointed ; on the 
clypeus are two gouge-shaped spines, shining black on outer half, and on the upper 
rooghened base of each of these there is a small conical tooth ; on the under side of 
the head-case, below the gouge-like spines, is a pointed spine directed forwards ; 
back of this are two smaller cusps, oue either side of ventral line, and still farther 
back, apparently over the first tarsal joiut of the forelegs, are two smaller points; 
the transverse rows of dorso-abdomiual teeth are as usual, but the teeth are exceed- 
ingly fine, increasing in size but little posteriorly; the black, blunt, anal segment 
bears several small black conical teeth on either side. 
