1878.] Mode of Extrication of the American Silk-Worm Moth. 455 
My attention was attracted by a rustling in my box of cocoons. 
The noise was traced to a cocoon which had been nearly flattened 
out during its previous sojourn in my coat-tail pocket, and whose 
development was, therefore, a surprise. I carefully cut an open- 
ing about a half an inch long, and a quarter wide on the top of 
the cocoon. The same method, I afterwards found, was employed 
by Mr. Trouvelot. I did not cut the flap entirely off, but left it 
so that the cocoon could be opened and closed at pleasure. All 
the motions of the chrysalis could be distinctly seen and studied. 
The back of the pupa had just begun to split. The positions of 
the “cocoon-cutters” were plainly marked by a pair of black 
protuberances on the shoulders. The end of the cocoon was 
well moistened. 
The first motion was up and down. The chrysalis resting on 
its head and tail, arched its body so that the middle of the ab- 
domen was thrust upwards. The object of this seemed to me to 
be the loosening of the moth from the pupa skin. This motion 
lasted about an hour, at the end of which the second motion be- 
gan; this consisted of a rotatory movement. Now, for the first 
time, the head was pressed against the end of the cocoon. The 
gloss was rubbed off of the moistened portion, and the strands of 
silk much loosened by this boring process. Both these motions 
were accompanied by a slight rustling, largely due, I think, to 
the crackling of the cast-off larva skin. 
All the preparations for exit having thus been made, the re- 
maining steps were quickly taken. The body of the moth came 
to rest, its wings were drawn up from their cases by a shrugging 
of the shoulders, if I may use the expression, which describes the 
motion exactly. The shoulders were then drawn together as 
nearly as possible, and, while pressing against the cocoon, thrust 
apart with considerable violence. A tearing sound was now 
heard, entirely different from any which had preceded it. The 
cocoon-cutters, though not visible from my “ coign of vantage,” - 
could be distinctly felt through the wet cocoon. Turning a little, 
the operation was repeated. After several repetitions, a weak 
spot was found, where the cutters were forced through. The 
small opening was quickly enlarged, the back of the thorax and 
the shoulders were thrust through, followed by the head, antenne 
and fore-legs, in the order named. The remainder of the task 
was readily accomplished, and the perfect insect emerged two © 
hours from the beginning of my observations. | 2 
