March, 1898 ] WEBSTER: DEVELOPMENT OF DRASTERIA ERECHTEA. 29 1 
size, each series comprising three individuals and measuring in length 
as follows: i inch ; i T V inches; ii inches, and inch; if inch ; 
and f inch. The larva measuring inch moulted on November 19th. 
On account of being almost continually absent from home, I was 
now compelled to turn the larvse over to my assistant, Mr. C. W. Mally, 
who gave them nearly all the attention they had throughout the re¬ 
mainder of the time that they were under observation. 
After December 1, the larvae appeared to increase in size very rap¬ 
idly, the larger ones becoming lighter in color, and could hardly be 
distinguished from the yellowish and brown blades of grass, more or 
less eaten, and along which they would stretch themselves and remain 
for a long time, occasionally moving the head from side to side with a 
sort of trembling motion. This protective coloration had been observed 
from the time of the first moult of the larvae, the brown stripes and 
greenish background blending with the discoloration of the part of the 
blades of grass that had been attacked, while the lighter green corre¬ 
sponded with the portions of uneaten epidermis, backed by the green 
color of the blades behind them. As the larvae became more aged the 
colors changed to a more decided brown hue, intermingled with yellow¬ 
ish, and with this change there came a decided disposition to pass more 
of the time nearer the base of the grass plants, where these colors pre¬ 
dominated, than higher up, where the prevailing color was a uniform 
green. Earlier in the life of the larvae, the upper portion of the blades 
of grass were more generally attacked, none being cut off from below 
and falling down to turn to yellow and brown, while now at this later 
period,many blades were eaten only for a short distance above the ground 
and falling down took on the yellow and brown. Whatever might 
have caused this change of habit, it was certainly not on account of the 
lower portions of the blades being more tender and succulent, though 
with the continually increasing bulk of the individual larva there would 
naturally follow a greater aversion to activity, and a less disposition to 
climb to the higher portion of the blades of grass.- It seems to me that 
we here have a most interesting case of adaptation, and one that was 
not anticipated when these observations began. 
On December 3 the three larger larvae began to show signs of un¬ 
easiness, crawling about the cages, and again stretched at full length on 
the side of the same, and again down among the grass, feeding. 
December 7, one of the larger larva, which will be hereafter desig¬ 
nated as No. 1, and the adult and chrysalis is shown under this number 
in the illustrations, settled down in a corner of the breeding cage, fas- 
