496 
ANNUAL REPORT OF NEW-YORK 
a dead, leafless limb of this tree two worms were detected upon 
the twenty-second day of June, reposing near each other. They 
crawled from this limb by night to feed upon the leaves of the 
other limbs and returned to it to repose during the day, as though 
conscious that such tumors or excrescences as their bodies imi¬ 
tated were natural to diseased and dead limbs rather than those 
which were thrifty and in full foliage, and that they therefore 
would be less liable to attract notice here than elsewhere. They 
were observed daily upon this limb for a week, when one of them 
having disappeared, the limb was cut off" to secure the other, 
although as I afterwards learned, the worm was now but half 
grown. 
The young larva is pale ash-gray, identical in its hue with that of the 
limbs on which it resides. Its surface is varied with minute brown points, the 
larger ones of which are impressed. Along the middle of the back is a narrow- 
black streak which is interrupted at each of the sutures. On each side of this 
is a row of small elevated black dots or warts, one on each segment, these dots 
giving out several black diverging bristles. On the outer side of each dot upon 
the fifth and the following segments is a small yellow spot. The fourth seg¬ 
ment or last one of the thorax is black above and on its sides and has a trans¬ 
verse cream yellow spot on its hind margin; and the three segments before the 
last are black above, between the black dots. The lappets or lobes along the 
sides of the body are black at their tips and yield a few black bristles, and un¬ 
der these and also along the sides of the lappets and of the body between their 
bases arise numerous diverging white hairs, which are appressed to the surface 
on which the worm is reposing. The head is ash-gray, with several blackish 
spots, and is clothed with gray hairs. 
The branch containing this worm was placed in a breeding 
cage, and also a twig clothed with leaves, and to this the worm 
immediately crawled, resting concealed among the leaves. JBut 
it was very intolerant of confinement, eating but little if at all, 
and in about a fortnight it perished. When in motion it has a 
very diflerent appearance from what it presents when at rest, 
being much longer and of a nearly cylindrical form. It moves 
in a hurried impatient manner, its gait resembling that of the 
hairy Arctian caterpillars. 
On carefully examining the tree on which these two worms 
were observed, July 17th, I was so fortunate as to find a mature 
worm and four cocoons. None could be discovered upon other 
larch trees in the yard, and these insects were probably the pro¬ 
geny of one single parent, which had strayed hither from a 
