STRUCTURE, FUNCTIONS AND (ECONOMY OF ARANEIDEA. 7l 



of July 1 84<3 had moulted seven times. It is apparent also from the particulars 

 already stated, that the intervals between consecutive moults are much shorter 

 when the temperature of the atmosphere is high than when it is low. 



Immature spiders infested by the larva of Polysphincta carbonaria, an insect 

 belonging to the family IchnmmonidcB, which feeds upon their fluids, never 

 change their integument*. 



Lilie certain animals of the class Crustacea, spiders possess the property of 

 reproducing such limbs as have been detached or mutilated, and this curious 

 physiological phsenomenon is intimately connected with the renovation of the 

 integument, as it is observed to take place at the time of moulting only. Ex- 

 periments illustrative of this interesting subject have been multiplied to a very 

 great extent ; in introducing some of them to notice, such have been selected, 

 as from the novel and important conclusions deducible from them are best 

 deserving of attention. 



1. A young male Textrix lycosina had half of the terminal joint of each 

 superior spinner amputated, and the posterior leg on the right side detached 

 at the coxa, on the 3rd of August 1838. It moulted on the 1 0th of September, 

 reproducing the detached parts, which were small but perfect in structure. 

 On the 23rd of February 1839 it moulted again and became adult; at the 

 same time a sensible increase took place in the bulk of the reproduced parts, 

 which, nevertheless, were still defective in point of size. 



2. On the 23rd of August 1838 a young female Tegenaria civilis had the 

 anterior leg on the right side and the third leg on the left side detached at the 

 coxa, the terminal joint of the superior and inferior spinners on the right side 

 being amputated at the same time. This spider moulted on the 27th of Sep- 

 tember, when the detached parts, of a smaller size than the corresponding 

 parts on the opposite side, but perfect in structure, were reproduced. On 

 the 6th of November it changed its integument a second time, and on the 16th 

 of June 1 839 a third time, when it arrived at maturity. The reproduced parts 

 advanced perceptibly in growth at each successive moult, but did not ultimately 

 acquire their lull dimensions. 



3. A young male Tegenaria civilis had the digital joint of the left palpus, 

 which was very tumid, detached on the 6th of October 1838. It moulted on 

 the 17th of June 1839 and reproduced the left palpus, which, though small, 

 had the radial joint provided with the apophysis characteristic of a state of 

 maturity in this species. The sexual organs, however, were altogether wanting, 

 and the digital joint was slightly modified in size and form by this circumstance. 

 It is scarcely necessary to remark that the sexual organs connected with the 

 right palpus were fully developed. 



4. The digital joint of the left palpus of a young female Segestria senoculaia 

 was amputated on the 18th of May 1839. This spider cast its integument on 

 the 8th of July, the left palpus, of a small size, being reproduced. It moulted 

 again on the 28th of June 1840, when the reproduced palpus had its dimen- 

 sions enlarged and the spider arrived at maturity. On the 12th of December 

 1842 it died, having existed nearly three years and a half in captivity. 



5. On the 8th of June 1839 a young female Agelena labyrinthica had the 

 terminal joint of each superior spinner amputated. Bringing the extremities 

 of the tarsi of the posterior legs to the mouth, it moistened them with saliva, 

 and repeatedly applied them to the mutilated parts. On the 21st of the same 

 month it moulted, and the superior spinners, of a small size, were reproduced. 

 It moulted again on the 12th of the ensuing July, when the reproduced spin- 

 ners were increased in size, and it arrived at maturity. 



6. A young male Textrix lycosina had the terminal joint of each superior 



* Annals and Magazine of Natural History, vol. xi. p. 1-4. 



