QEA PLE ino. 
MOULTING HABITS OF SPIDERS. 
I, 
YounG spiders usually make the first moult within the cradle where 
the eggs have been laid. The young of Lycosa and Trochosa remain: in 
. _ the cocoon until the second moult, after which they emerge and 
Moulting (amber upon the mother’s back, where the third and fourth 
of Young. : ae: 
moults occur before the little fellows begin independent house- 
keeping in miniature burrows of their own. Wagner asserts! that the 
mother softens and partly tears the cocoon at its selvage, thus aiding the 
exit, and that without such help the little ones fail to escape, and die; a 
statement which I feel sure must be modified. Young Attoids, having 
undergone the moult, shift their positions to the opposite end of the 
cocoon, and then moult a second and even third time before egress; as is 
shown by the fact that one finds within the same cocoon three separate 
heaps of skins cast at different ages. 
The subject of cannibalism within the cocoon has already been consid- 
ered,? with the general conclusion that it is rare among spiderlings, but 
sometimes occurs. The Trochosas observed by Wagner would 
appear to be among the exceptions; for not only does the mother 
in captivity devour her broodlings, but the latter feed upon one 
another, a fact which is closely related to differences developed at the 
moulting period, At the end of two or three months a considerable differ- 
ence in size appears among the young of the same brood ; some are more 
vigorous and agile, others feeble, and those weaklings commonly fall a 
prey to their stronger fellows. 
The cause of this inequality is traced to the fact that the eggs do not 
all hatch at one time, and that a whole day or more may intervene 
between the hatching of one division and another. In general, one remarks 
in a cocoon, at the second moulting period, one group whose individuals 
lack two or three days of the time, others on the eye’ thereof, and still 
others in the act of moulting. This circumstance alone will explain why, 
after two moults, the stronger spiderlings are able to overcome and eat 
the feebler ones. It would thus seem that only the more vigorous enter 
upon independent life, while the feebler or those which come more tardily 
from the egg contribute to the perpetuation of the species by yielding 
Canni- 
balism. 
1 La Mue, page 344. 2Vol. II., page 209. 
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