GENERAL COCOONING HABITS OF SPIDERS. 151 



black. I named the species Attus opifex, but according to Professor Peck- 

 ham it belongs to the genus Phidippus. 1 



I present in this connection a fac simile drawing of perhaps the earliest 

 sketch of a Saltigrade cocooning nest. July 26th, 1745, Baron De Geer 

 found among the needle like leaves of a pine tree a large, oval cocoon 

 nest of white silk, which was woven around the branch and interlaced with 

 the leaves. (Fig. 186.) The spider was inside along with her little ones, 

 who were present in great number. In the middle of the cocoon nest, at 

 the side, was a door, at which the spider stayed on guard ; but generally 

 she was within the tent with her little ones, preferring the back or middle 

 part thereof, near the supporting branch. De Geer found at the entrance 

 detritus of flies and other insects which had been devoured by the mother, 

 such as the legs, wings, etc. 



The spiderlings accompanied the mother, and appeared to live on good 

 terms with her. They were about a line long, but otherwise quite resem- 

 bled the mother, having black bodies and brown legs. They moved with 

 great vivacity and appeared to be nourished, in common with their mother, 

 by the prey captured by the mother. The species appears to be Dendry- 

 phantes hastatus Clerck. 2 



VI. 



Among Laterigrades a very general habit is to spin a piano convex 

 cocoon of tough silk fibre, which is attached to some surface. Sometimes 

 a light shelter tent is spun over this, and the 

 spider will be found dwelling within. (See Vol. L, 

 page 347, Fig. 338.) Thomisus cristatus Clerck, 

 of Europe (Xysticus audax Koch), secludes her- 

 self in the leaves and stretches some isolated 

 threads around her, and there sometimes she sus- 

 pends herself. In this retreat the female lays her 

 eggs in a flat cocoon, one-fourth inch in diame- 

 ter, the tissue of which is swollen by the eggs, 

 and presents rounded eminences. The spider places 

 herself upon the cocoon and does not abandon it 



when touched. The cocoon contains one hundred ^ f 



eggs of yellowish white color. 3 



The eggs of Philodromus are usually enclosed within a cell which is 

 hung among the leaves or stretched between twigs. (Fig. 187.) The egg 

 sac is surrounded by a slight silken tent, wherein the mother dwells. An 

 example of Philodromus mollitor, in my collection, 4 is woven in the angles 



1 "North American Spiders of the Family Attidse, Phidippus opifex McCook." Trans. 

 Wisconsin Acad. Sci., Vol. II., 1888, page 20. 



2 De Geer, pages 286, 287. 3 Walckenaer, Apteres, Vol. I., page 523. 



4 This example was sent me by Dr. Geo. Marx as the cocoon of this species. 



