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 spun 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 antenna), 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 
