380 : Extrication of Silkworm Moths. [ June, 
escape by means of a fuid. Thus we are informed by Dr. Rox- 
burgh that Aźtacus paphia when prepared to assume the imago, . 
discharges from its mouth a large quantity of liquid, with which 
the upper end of the case is so perfectly softened as to enable the 
moth to work its way out in a very short space of time, an oper- 
ation which, he says, is always performed in the night. Perhaps — 
the two opinions may be reconciled by supposing the silkworm 
first to moisten and then break the threads of its cocoon. In 
those that are of a slighter texture, a mere push against the 
moistened end is probably sufficient, and hence we find in so 
many newly-disclosed moths the hair in that part wet and closely — 
pressed down. it be apparently difficult for the silkworm 
moth to effect an opening in its cocoon, how much harder must 
seem the task of the puss moth (Cerura vinula) to pierce the solid 
walls of its wood-thickened case? Here the eyes are clearly 
incompetent; nor could any ordinary fluid assist their operation, 
for the gum which unites the ligneous particles is indissoluble in 
aqueous menstrua. You begin to tremble for the fate of the 
moth incarcerated in such an impervious dungeon, but without 
cause; what an agueous solvent cannot effect, an acid is com- 
petent to, and with a bag of such acid our moth is furnished. 
The contents of this she pours out as soon as she has forced her 
head through the skin of the chrysalis, and upon the opposite 
end of the cocoon. The acid instantly acts upon the gum, 
loosens the cohesion of the grains of wood, and a very gentle 
effort suffices to push down what was a minute ago so strong a 
barrier. 
Our attention was called to this subject by a rustling, cutting 
and tearing noise issuing from a cocoon of Actias luna, the large 
green swallow-tailed silkworm moth. On examination a sharp 
black point was seen moving to and fro, and then another, until 
both points had cut a rough irregular slit, through which the 
shoulders of the moth could be seen vigorously moving from 
side to side. The hole or slit was made in one or two minutes, 
and the moth worked its way at once out of the slit. The wings 
at this time being very small and flabby, and the shoulders being 
alternately much raised, the points stuck up far enough to cut oF 
saw through the cocoon. The wings were at first of a deep buff 
yellow, but in half an hour after, the wings began to expand more 
than before and to turn green. The black points, when the 
_ wings are fully expanded, can be detected, not being entirely cov- 
ered by the hairs at the base of the wing. In this case no fluid — 
=~ was seen to exude from the mouth, and the cocoon was per- 
— fectly dry. 
Oe ee EE I EAS N AA ee E TO UE AA SEN ee 
