11 
ence to healthy ones, can not be doubted, for the larva is abundant 
in the dead wood of a dying tree but occurs very rarely in the liv¬ 
ing tissue. 
The Elm-borer 
Saperda tridentata Oliv. 
In the larval or boring stage this elm insect may be readily 
recognized by those at all familiar with the round-headed borer of 
the apple, because of the close resemblance of the two. They be¬ 
long, in fact, to nearly related species of the same genus. 
Fig. 1. The Elm-borer, Saperda 
tridentata , larva. (Enlarged 5 dia¬ 
meters.) 
The full-grown boring larva (Fig. i) is a footless grub a little 
over an inch in length, white or yellowish white, thickest in front, 
and with the head only about half as wide as the first segment be¬ 
hind it. The body is slightly flattened from above downward, with 
a rather pronounced fold along the sides. The first segment is 
