178 Mr. J. Black wall on certain Phenomena in the 
though 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 j 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 quadrat a, 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 triangidifer, are given by Baron 
Walckenaer in his ^ Histoire Naturelle des Insect es Apteres,^ 
supplement ii Fhistoire naturelle de Pordre des Araneides, t. ii. 
p. 506 : — “ Prise ala fin de decembre 1839, cctte Araneidc 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 
