THE HOUSE SPIDER 187 



would indicate that soone of the spiderlings hal slain their brot-. 

 ers. Cannibalism is known to exist among the young of other 

 species, and it certainly exists to a limited extent in T. tepidarior- 

 um,. The writer is of the opinion that those individuals that 

 first reach the second nymphal stage (the first active stage) 

 habitually feed upon the other spiderlings in the cocoo i that are 

 in the first nymphal, or quiescent stage. The presence of 15 

 unfertilized eggs is not to be wondered at. The percentage of 

 unfertilized eggs in many cases will amount to 50 per cent. 



Some counts were made to find out the number of spiderlings 

 emerging from a cocoon. Twelve days after the first spiderlings 

 had emerged from a cocoon a count was made of them and there 

 were 115. Not a single dead one was found in the breeding 

 cage, and since 12 days had been allowed for their emergence 

 probably all were out that would come out. In another case a 

 count was made, at least 8 days after the beginning of the emer- 

 gence of the spiderlings. This time 254 individuals were found. 

 All of these were alive except probably two or three individuals. 



Number of Cocoons SpiiAi in a Season. — ^McCook states in re- 

 gard to the number of cocoons spun by T. tepidariorum, "It 



spins during the season from three to five ovoid cocoons " 



In another place he mentions finding a dozen cocoons in the 

 meshes of a single snare. Undoubtedly the number of cocoons 

 spun during the year depends largely upon the food supply. If 

 the female is properly fertilized and amply fed she will spin 

 more than five cocoons in a season. A female which was cap- 

 tured by the writer April 12, and kept in captivity spun nine 

 cocoons before her death, which occurred between October 9 and 

 November 27. Another female which was captured May 4, 

 probably a few days before she was mature, did not do so well. 

 She spun four cocoons during the season, dying before November 

 25. 



That the female spins several cocoons has been known for a 

 long while, for three or four or even more Avill frequently be 

 found on a single snare. Of course it is not always known that 

 the cocoons found on a single snare are those made by a single 

 female, but usually they are. Mature females as a rule do not 

 desert their snares, but immature females have been observed 

 by the writer to adopt old snares. This they frequently do, 

 especially where the spiders are so numerous as to cause some 

 crowding. 



