372 PROCEEDINGS OF THE ACADEMY OP [1887. 



Reckoning its death as having occurred at the close of July 1887, 

 the spider was five years and three months in my possession. I have 

 not sufficient data to estimate accurately the rapidity of growth in 

 this species, but judging from such facts and indications as I have 

 observed, I do not hesitate to reckon the animal to have been from 

 eighteen months to two years old when I received it from Dr. Leidy. 

 At the period of its death, therefore, it must have been at least seven 

 years old, and may have been eight. It has thus attained the dis- 

 tinction of having reached the greatest age of any spider known to 

 science. How long this species and members of the Theraphosoidse 

 generally live in their natural habitat is of course unknown. I have 

 no doubt that they live much longer than spiders of the other great 

 sections or groups, but am inclined to think that it is not usual for 

 them to reach such on age as my tarantula "Leidy." In its case, 

 as in that of Sir John Lubbock's queen ant, human protection 

 probably aided to prolong life. 



Such observations as have heretofore been made upon the age of 

 spiders fall in with the general indications as to their vital endur- 

 ance made by the prolonged age of this tarantula. Blackwall, 

 the veteran British araneologist, kept spiders of the species Tegenaria 

 domestica and T. civilis to the age of four years.^ Moggridge made 

 a calculation upon the age of trap-door spiders based upon the aver- 

 age growth in the nests of the young, for he established the fact 

 which has subsequently been confirmed that the young spider instead 

 of abandoning its nest enlarges it with its growth. The conclusion 

 of this calculation was that it took at least four years to produce a 

 full size trap-door nest, and of consequence the architect must be at 

 least that old." The most recent information upon this point is given 

 by Mr. Fredrick Enock in a paper published two years ago.* 

 This observer in an extended and interesting communication upon 

 the habits of the British Atypus speaks of one individual which he 

 had in his possession over three years, and which, judging from its 

 size when first captured, he puts at the age of six years. Other 

 examples which had been under observation for more than two 

 years were well grown when first transferred to his artificial colony, 



1 "Spiders of Great Britian and Ireland." p. 8. 



2 Moggridge. "Harvesting Ants and Trap-door Spiders." p. 127. 



3 "Tlie Life-History of Atyptis picens, Sulz." Transactions Entomological 

 Society of London. 18So. p. 416. 



