THE LIFE OF THE SPIDER 41 



tures are developed. No setae or hairs are present on any part 

 of the body. The shape and size of the eyes are sometimes indi- 

 cated even at this stage, but they are colorless and without func- 

 tion. In the abdomen is an abundant yolk material on which the 

 creature can subsist until able to feed. The deutovum grows 

 quickly after emerging from the egg covering, and soon is twice 

 as large as the space occupied by the egg. The duration of the 

 deutovum stage is usually quite short, and toward the end of it 

 we begin to see the darker coloration of the growing spiderling 

 beneath the cuticle. 



The first true molt, always undergone while in the egg sac, 

 brings to light the creature that we all recognize as a spider, and 

 which is truly a miniature of the adult. During a rather indefinite 

 period of its life, perhaps for several stadia, it is referred to as a 

 spiderling because of its small size. The legs are now longer, 

 much more slender, and clothed with darker spines and hairs. At 

 the tip of the tarsi are found tarsal claws, two or three depending 

 on the family to which the spiderling belongs. The spiderling is 

 now able to spin but it uses little silk until after it leaves the 

 egg sac. The digestive system is more perfectly developed, and 

 the spiderling is probably able to feed, but its food requirements 

 are still being met by unused yolk material in the abdomen. 



What happens next is largely dependent upon the tempera- 

 ture. If the weather is favorable, the spiderlings become active 

 and move about in the sac, their actions dependent upon the de- 

 gree of warmth that penetrates through the silken covering of their 

 domicile. Some female spiders guard the egg sac until they die, and 

 others are reputed to aid their babies to escape from the sac by 

 tearing it open. In most cases, however, the female has long since 

 died and the escape must be effected by the spiderlings themselves. 

 In tough sacs they usually cut a neat round hole, through which 

 they emerge one by one, or, in weaker sacs, they will force a large 

 rent. Following emergence comes the dispersal of the family, usu- 

 ally by ballooning. 



If the weather is cold, the spiderlings in the cocoon are inac- 

 tive. They often stay in the egg sac through the whole winter, 

 awaiting the proper temperature in the spring before dispersing. 

 This is particularly true of those species that lay their eggs late 

 in the fall, when not enough time and warmth are available to 

 allow the spiderlings to develop and disperse. 



