1887.] NATURAL SCIENCES OF PHILADELPHIA. 373 



and at the date of his paper, June 1885, were still in good health. 

 He ventures the inference that Atypus is about four years in 

 reaching maturity, then retains her young for eighteen months 

 under her care before turning them out to shift for themselves, and 

 after that lives in vigorous health for a period which he believes 

 may sometimes reach the advanced age of ten years. 



I may add here, as in the same line of research, that Dr. George 

 H. Horn a distinguished authority in the Coleoptera, has called 

 my attention to the fact that a female of Cybister roeselii was 

 preserved for eight years of continuous life by Dr. David Sharp. 



As has been stated, my tarantula died in the act of or in conse- 

 quence of casting its skin. It has usually been accepted as a fact 

 that the final moult of spiders is made j ust before the attainment of 

 maturity. Unfortunately the decayed condition of the carcass does 

 not permit me to determine the question in the case of this particu- 

 lar individual. But these interesting queries are suggested: did the 

 artificial conditions of the spider's life so influence its organism as 

 to retard the functions that result in the act of moulting ? Are we 

 therefore to consider this final moult, accomplished at the age of 

 seven years or thereabouts, to have been abnormal as to the time of 

 its occurrence ? Or, may we infer that this represents the normal 

 pei'iodicity of moulting and of consequence that the mature spiders 

 of this family, which are so frequently taken in various parts of the 

 earth, are all of them as old as the one whose history I have been 

 noting ? 



III. Habits of the American Tarantula, 



1. Moulting and its dangers. During its confinement "Leidy" shed 

 its skin several times. The first moult occurred sometime in August 

 1882. I had been absent on my usual summer vacation and return- 

 ing August 31st, saw the animal lying on the soil about the middle 

 of its glass nest with its feet gathered together looking dull, gray 

 and faded out apparently dead. I shook the globe. No response 

 was made by any action, and as I was at the time in a great hurry, 

 I left without more careful observation, concluding that the spider 

 was dead. I was not able to visit it again until the fifth day of 

 September following. I threw off" the cover of the globe and put 

 my hand in to take out the dead body, wliich lay apparently in the 

 same position, in order to preserve it in alcohol. As I touched it 

 the animal leaped to its feet, and as I hastily withdrew my hand 

 thankful for the danger which I had escaped, for the creature bears 



