266 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
from 11% to 2 inches in diameter (fig. 57). It occurs in the Eastern 
and Central-Western States. The eggs are laid early in the summer 
in a small hole gnawed through the bark. The young larvae feed 
beneath the bark. later entering ; the wood, as the gall-like swelling in- 
creases In size. Finally a str aight burrow is extended up or down the 
center of the stem, at the end of which the larva pupates. Little frass 
is exuded. The galls produced by this insect on ornamental plants 
eecasionally cause the death or breaking off of the branches. Control 
measures are given on page 24. 
FIGURE 57.—Galls of Saperda concolor on poplar. 
The adult of Saperda fayi Bland., the thorn-limb borer, is a small 
reddish-brown beetle from 10 to 12 mm. in length. The under side is 
gray, and the upper surface bears white blotches arranged as two 
stripes on the thorax, two at the base and tip of the elytra, and a large 
spot between these. The habits are similar to those of S. concolor, 
this species causing galls on thorn apples in the Northeastern and 
Central States. Another species with similar larval habits, causing 
galls on the stems and branches of poplar across the northern parts 
of the country, is S. moesta Lec., the poplar-twig borer. The adult 
of this species measures about 10 mm. in length, is uniformly dark 
eray in color, darker than S. conco/ov, and the antennae are annulate, 
Control measures suited to these borers are given on page 24. 
