SCHEFFER : COCOONING HABITS OF SPIDERS. 109 



balls. The latter consist of a rounded agglomeration of per- 

 haps fifteen whitish eggs, held together by a few threads, but 

 having no external covering other than such of these threads as 

 extend from the outer surface of one egg to another. The 

 whole mass is about three-eighths of an inch in diameter, and 

 resembles in shape a small blackberry. It is held in front of 

 the female by means of her chelicerse and pedipalps. She con- 

 tinues to carry about the little cluster of spiderlings for some 

 days after they hatch. The period of incubation is a little less 

 than two weeks. 



Family PISAURID^. 



Of the Pisaurida?, two genera, Dolomedes and Pisaura, are 

 more or less common in the United States. They are wander- 

 ing spiders, living along streams. One genus of the family, 

 from foreign parts, spins a permanent web, but all the others 

 make use of a web structure only when rearing their broods. 

 All carry their cocoons about with them until the eggs are 

 ready to hatch. Then they spin a silken shelter among leaves 

 and branches, and, depositing their treasure there, guard it 

 jealously and constantly. The young remain for some days or 

 weeks in this shelter, living a sort of communal life. Appar- 

 ently the mother never deserts them until they disperse to shift 

 for themselves. 



Species of the two common genera mentioned above carry 

 their cocoon in the chelicerae, holding it close to the sternum. 

 Some other genera are more like the Lycosid* in the manner 

 of carrying the cocoon, for they have it attached to the spin- 

 nerets by a bundle of threads. In the first case — those that 

 carry ifc in the chelicerse — the cocoon is quite well rounded, and 

 consists of a single piece of continuous tissue ; in the second 

 case it is more flattened, and is made up of two valves, one of 

 which, the lower, is quite flat, the other very convex. 



Type : Dolomedes rufus. 



A very large, long-legged spider frequenting watercourses. 

 In July and August the female deposits her eggs in a globular 

 cocoon about the size of a common cherry. It is all of one 

 piece and is probably whitish at first, but soon becomes dis- 

 colored. The mother takes it up and carries it about in her 

 chelicerse until her instinct tells her that the eggs are about to 



