264 LARCH CHEATER ITS LARVA. 



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 

 limhs on which it resides. Its surface is^ varied with minute brown points, the 

 larger ones of which are impressed. Along the middle of the hack 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. But 

 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 different 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 



