486 SUPPLEMENT 



spider passes the winter in a thick web, which it has made for 

 itself, and from which it does not issue forth until the middle 

 of February. But it results from observations collected re- 

 specting other species, that they also form a cocoon with 

 another view, namely, that of preserving their posterity, and 

 sheltering themselves at those critical periods when they 

 change skin. 



Degeer found, at the end of July, on a branch of pine, a 

 large oval cocoon, of white silk, placed around the branch, 

 and intertwisted with its leaves. It was the dwelling of one 

 of those leaping spiders, and of its young, which were living 

 along with it, in a state of good intelligence, and appeared to 

 subsist in common on the prey taken by it. On the middle of 

 one of the sides of the cocoon was a cylindrical aperture, a 

 sort of door, where the mother used to remain in ambush. 

 The same observer found under stones, on the shores of the 

 Baltic sea, many individuals of another species, resembling 

 an ant, which M. Walckenaer has placed in a particular 

 family. All the individuals were lodged separately in small 

 oval cocoons of white silk, having an aperture at each end, 

 and which they had Si)un against the under-side of the stones. 

 If he touched their cocoons ever so slightly, they would issue 

 forth from one of the apertures, and betake themselves to flight 

 with great rapidity. When he wanted to take them, they 

 easily escaped, by suffering themselves to descend on a thread 

 of silk. They abandoned their nests without any difficulty, 

 as they were able very speedily to construct new ones. 

 Degeer has witnessed their changing skin. When they walk, 

 they stop short at intervals, raise the two anterior feet in the 

 air, agitate them up and down like antennae, and feel the 

 ground with them, as they would with true antennae. They 

 would then appear to have but six feet. The individuals of 

 this species, which this naturalist kept in a sand-box, seemed 

 to dread each other extremely. When they met, they first 



