factors, among which may be numbered too close growth, defective 
drainage, insufficiency or a superabundance of subterranean moist- 
ure, or too great dryness; or, again, it might be produced by a dry spell 
suddenly followed by an unusually wet one, or vice versa. In the 
present case it seems more than probable that the soil had undergone 
some change that interfered with the growth of the trees, or that a 
combination of unfavorable atmospheric and soil conditions accom- 
plished the supposed predisposing debility. The withering and dying 
of leaves induced by a spell of 
hot, dry weather following cool, 
moist weather, and known as 
sun scald, might be provocative 
of the debilitated condition fa- 
vorable to the attacks of this 
borer. 
DESCRIPTION OF THE INSECT. 
For the identification of the 
beetle and its larva, the accom- 
panying illustration (fig. 1) is 
presented. The beetle, shown 
ON ? ' : Fie. 1.—Agrilus Dilineatus: a, adult beetle; b, 
at a, 18 elongate and subeylin- antenna of same; @°, claws of posterior tarsi 
drical, like others of its genus. of female; <, same of male; ¢c, larva; d, pupa— 
It is black, with a more or less eae EA aE RATE Se eS 
greenish tinge. The sides of the 
thorax and elytra are clothed with light golden-yellow pubescence, 
and the elytra are each marked with a stripe of the same color. It 
measures about three-eighths of an inch in length, and is fully three 
times as long as wide. An enlarged antenna is shown at the left 
(a), and below are the claws of the hind feet of both sexes. The 
larva, drawn to the same scale as the beetle, is illustrated at c. It 
is long, slender, and considerably flattened. In color it is milk white 
or slightly yellowish, except the mouth-parts and the peculiar anal 
fork, which are dark brown. Its length is nearly twice that of the 
adult beetle. The pupa, which is white hke the larva, is shown at d. 

DISTRIBUTION; TIME OF APPEARANCE. 
This species is native to the United States, occurring from Maine 
and Massachusetts southward to Texas and westward to the Rocky 
Mountains. It will thus be seen that the species occupies what are 
known as the transition, upper and lower austral life zones; but 
injuries have been reported only from the upper austral zone, which 
comprises a considerable portion of the most fertile and most popu- 
lous parts of our country and that portion in which the chestnut 
attains its highest development. The districts in which injuries have 
