42 
the signs of its presence should be generally known, in order that 
it may be promptly recognized and suppressed upon its appearance 
in any new locality. 
Injury by this borer may be suspected when the general health 
of a tree is evidently affected, where there are dead patches of the 
bark, irregularly cracked open (Fig. 44, 45), or where openings in 
I 
Fig. 44. Injury by Poplar and Wulow Borer, 
Crypt orhynchus iapathi. 
the bark give exit to a soft excrement like moist sawdust mixed 
with fine splinters. The burrows beneath the bark, made chiefly in 
the cambium layer, are irregular in direction, sometimes girdling a 
small tree, and show nothing of the symmetrical pattern made by 
many borers which undermine the bark. Those of the older larvae 
dip into the w'ood, usually reaching the center of the branch unless 
this is large. These deeper burrows finally become filled with 
powdered wood and splinters, except a chamber at the farther end 
in which the larva pupates. In the active boring stage these in- 
sects are soft, yellowish, fleshy, cylindrical, footless grubs (Fig. 
46) with a pale-brown head and darker mouth-parts. They are 
half an inch long when they reach full size, which is about the last 
of June for those most advanced. At this time, however, young 
larv?e may be found under the bark down to a fifth of an inch in 
length. 
The adult beetles (Fig. 47) begin to appear in July, and con- 
tinue abroad at least until October. They are well marked and 
easily distinguished insects, a little more than a quarter of an inch 
