Pomona College, Claremont, California 131 



no eggs ol the trap door spider collected, 1 cannot consider the 

 shape oi the egg case and none oi the authors ol spider life his- 

 tories describe it. Comstock speaks oi finding one in Florida, but 

 docs not describe it. 



rhe genera] shape oi the coo- cases ol the different species studied, 

 seemed to be the same in ;ill ol the coo cases ot that species. Corn- 

 stock says in regard to the constancy ol the shape ol the egg sac oi 

 the species, " rhe coo sac is not merely a covering made in a hap- 

 hazard way; but is a more or less elaborate structure, made in a 

 definite manner characteristic ol the species." While one cannot 

 determine the species or genus ol a spider definitely by the shape 

 of its coo sac, yet it is a small factor which might aid in telling 

 the genus. 



rhe young oi the different species differed widely in the length 

 oi time oi emerging. Peucetia viridans emerged in a month, 

 Arenea ijt- imii it in from two to three weeks, Lycosa sp. in three 

 weeks, Phippdus sp. was kept tor seven months and then artificial 

 help was given to open the sack. The eggs oi most oi these species 

 hatched soon alter being laid. 



I he spiders made {i]]c or more moults in the coo sac before 

 emerging from the case. In the case oi Aranea it was seen that a 

 great pile oi shed skins were exuded outside oi the sac iust before 

 the young emerged and then while emerging from the sac they 

 went through another moult, leaving their shed skins in the case or 

 lust outside on a line which they made. From observations it 

 would seem as though this species moulted two or three times 

 before emerging from the sac. "The young attids, having under- 

 gone the moult, shift their positions to the opposite end oi the 

 cocoon and then moult a second and even third time before egress; 

 as is shown by the fact that o]\e finds within the same cocoon three 

 separate heaps oi skins cast at different ages." The young with 

 the aid ot a great deal ot heat emerged two weeks after the eggs 

 were laid. 1'hcv had not moulted at all ami were very weak, and 

 came from one end ol the cocoon. Flic case that was left tor seven 

 months showed that the young had deposited their shed skins in 

 three places before emerging, and having migrated from one end 

 o( the egg sac to the other. Wagner ('88) asserts in "La Mue" — 



