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 ^^g 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 Qg% 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 



