l78 Mr. J. Blackwall on certain Phanomena in the 



thougli small, will be proportionate to those of the corresponding 

 limb on the opposite side ; whereas it is evident from the prece- 

 ding experiments that legs and palpi restored after mutilation are 

 never symmetrical except when respectively developed in the un- 

 detached coxa and axillary joint alone. 



So little appears to have been done for the purpose of deter- 

 mining the longevity of spiders with some approach to accuracy, 

 that a few observations on the subject probably will not be re- 

 garded as superfluous. 



A young female Tegenaria civilis, disengaged from the egg on 

 the 6th of July 1842, after quitting the cocoon was placed in a 

 separate phial and was abundantly supplied with nutriment. 

 It continued in excellent health and condition apparently till the 

 8th of July 1845, when it died suddenly, having completed the 

 third year of its existence. 



On the 27th of June 1842 a young male Tegenaria civilis was 

 disengaged from the egg. It quitted the cocoon on the 21st of 

 the following month, and underwent its last moult on the 17th 

 of October 1843. During the winter of 1844 it became greatly 

 reduced in bulk, and died on the 30th of March 1845. 



The egg of a Tegenaria civilis hatched on the 27th of June 

 1842 produced a female spider, which completed its final change 

 of integument on the 5th of August 1843. It took its food well, 

 and appeared to be in good health till the 6th of July 1846, when 

 it died, having attained to the age of four years and nine days. 



Allowing for the disadvantages to which spiders are subjected 

 in a state of captivity, I think the duration of life in the species 

 upon which the observations were made should not be estimated 

 at less than four years, and I have elsewhere shown (An- 

 nals and Magazine of Natural History, vol. xv. p. 232, experi- 

 ment 4 ; and pp. 235, 236) that the life of Segestria senoculata 

 is protracted to an equally long period. Whether any spiders 

 enjoy a more prolonged existence or not remains to be ascer- 

 tained ; but there can be no doubt that Dolomedes mirabilis, Clu- 

 biona erratica, Agelena labyrinthica, Ep'eira quadrata, Tetragna- 

 tha extensa, Linyphia montana, Theridion lineatum, and nume- 

 rous other species, do not usually survive the second winter after 

 quitting the egg in this northern climate. 



The following particulars, extracted from observations made 

 by M. Doumerc on Theridion triangulifer, are given by Baron 

 Walckenaer in his ^ Histoire Naturelle des Insect es Apteres,' 

 supplement k Fhistoire naturelle de Pordre des Araneides, t. ii. 

 p. 506 : — " Prise a la fin de decembre 1839, cette Araneide fit un 

 premier cocon le 23 avril suivant, les oeufs ont eclos le 5 mai ; 

 il n'en est sorti que des males. Le 10 mai, formation d'un nou- 

 veau cocon ; le 24 mai, les oeufs ont eclos, il n^en est sorti que 



