Pomona College, Claremont, California 131 
no eggs of the trap door spider collected, I cannot consider the 
shape of the egg case and none of the authors of spider life his- 
tories describe it. Comstock speaks of finding one in Florida, but 
does not describe it. 
The general shape of the egg cases of the different species studied, 
seemed to be the same in all of the egg cases of that species. Com- 
stock says in regard to the constancy of the shape of the egg sac of 
the species, ‘“The egg 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 of the species.” While one cannot 
determine the species or genus of a spider definitely by the shape 
of its egg sac, yet it is a small factor which might aid in telling 
the genus. 
The young of the different species differed widely in the length 
of time of emerging. Peucetia viridans emerged in a month, 
Arenea gemma in from two to three weeks, Lycosa sp. in three 
weeks, Phippdus sp. was kept for seven months and then artificial 
help was given to open the sack. The eggs of most of these species 
hatched soon after being laid. 
The spiders made one or more moults in the egg sac before 
emerging from the case. In the case of Aranea it was seen that a 
great pile of shed skins were exuded outside of the sac just before 
the young emerged and then while emerging from the sac they 
went through another moult, leaving their shed skins in the case or 
just 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 of the 
cocoon and then moult a second and even third time before egress; 
as is shown by the fact that one finds within the same cocoon three 
separate heaps of skins cast at different ages.” The young with 
the aid of a great deal of heat emerged two weeks after the eggs 
were laid. They had not moulted at all and were very weak, and 
came from one end of the cocoon. The case that was left for seven 
months showed that the young had. deposited their shed skins in 
three places before emerging, and having migrated from one end 
of the egg sac to the other. Wagner (’88) asserts in “La Mue”— 
