8 Farmers’ Bulletin 1154. 
DESCRIPTION. 
The adult (fig. 9) is an elongace, robust, grayish-green beetle, meas- 
uring from 21 to 30 mm. (about an inch) in length, and having faint 
yellowish spots on the wing covers. The antennz or horns are very 
long, those of the female being about the length of the body, and 
those of the male even longer. | 
The larva is an elongate, cylindrical, footless grub of a whitish or 
yellowish white color. When full grown it measures from 30 to 35 
mm. (about 14 inches) in length. It can be distinguished from all 
Fic. 5.—Split sections of aspens showing larval mines and pupal cells of the aspen 
borer, and the character of the frass. The smaller holes on the bark section are 
exudation pores from which frass is expelled by the larve. 
other wood borers in the trunk or large branches of poplars by the 
fact that it has the sides of the head parallel and the upper and lower 
surfaces of the body covered with fine horny points. On the first 
segment above, these are larger and curve backward. Two dark 
oblique lines are present on this segment in related species of poplar 
borers, but never on this insect. 
The pupa, or intermediate stage between the larva and adult, has 
the same general form as the adult, but with its wings and legs 
folded along the side of the body. It is of a whitish color and the 
upper surface is provided with small horny spines. 
NATURAL ENEMIES. 
A tiny, wasplike, four-winged parasite which attacks the eggs of 
the borer has been reared and found very destructive to *them. 
