432 TRANSFORMATIONS OF INSECTS. 
it corresponds to the vent. At this stage of the development 
the young spider gives no sign of motion, but at length, when 
all is completed, it bursts the egg by tearing through the outer 
membrane. 
According to De Geer this outer membrane becomes fissured 
along the chest-piece of the spider, which protrudes its head, 
the mandibles, thorax, and abdomen; after which there remains 
the more difficult operation of extricating the legs and maxillary 
palpi from that part of the external membrane with which these 
parts are as it were enveloped. 
This is at length effected, though slowly, by alternately 
dilating and contracting the body and legs, upon which the 
spider is liberated and soon becomes capable of progression. 
As the parts are disengaged from the skin-like membrane it 
is pushed towards the ends of the legs, and is reduced to a 
little white bag, which is all that remains. Sometimes the pellicle 
is found still slightly adherent to the abdomen, but the spider 
soon frees itself entirely from it. This is the mode in which 
the young spiders of every species disembarrass themselves of 
the egg covering, and the operation is analogous to that of 
moulting. This is, however, only the first birth; all the parts 
of the spider, the head, jaws, legs, and abdomen, are still enveloped 
in a membrane which furnishes a sort of sheath to each. 
The spider is embarrassed in all its movements; it changes 
its situation with apparent pain, and is unable to construct a 
web and seize its prey. It seems, indeed, to be stupid and 
indisposed to action. To this end, and in order to be fit for 
moving about, it is necessary that the spider should free itself 
of this other covering, and then only it can be said to see the 
light. This last operation, or, as it may be called, the first moult, 
takes place after a period varying according to the degrees of 
atmospheric heat and moisture. Sometimes it is observed within 
the first week, at others it is not effected before the end of several, 
for in every instance the moult takes place in the woolly net 
or general covering of all the eggs, and the young spider does 
not quit this common nest, except in fine weather, until generally 
in the months of May and June. 
Before arriving at the adult stage the spider changes its skin 
