478 
SUPPLEMENT 
composed of the same material. It is round, white, formed 
of a single stratum, and the tenuity of its walls allows the 
egg to be perfectly well distinguished. Clerk has counted 
about one hundred and forty of them. They are the size of a 
grain of beet-root, spherical, of a clear shining white, with 
white circles on one of the sides. They are exceedingly 
smooth, and when placed on paper they roll like little drops 
of mercury. They are seen to go equally from one side to the 
other in the cocoon, not being agglutinated. The female 
fixes herself in the midst of the packet of leaves, to watch for 
the preservation of her posterity. Clerk tells us that the 
young are born towards the end of July. 
It is more particularly to the species of the genus Tho- 
misus, that Europeans give the name of crab-spiders . They 
are seen running on the ground, climbing on the bushes, on 
plants, and even on elevated trees, from which they often 
descend by means of a thread which they unwind, and by 
means of which they can reascend. Accordingly Lister has 
compared them to rope-dancers. Contracting their feet against 
their body, they balance themselves in some sort, in the air, 
impress a movement on their thread, and direct it as if nature 
had given them wings and oars. Degeer also tells us, that 
these araneides unwind always in walking, a thread which is 
attached to the place where they were seated. They are 
again to be met with in the corollae of flowers, where they 
seize the little insects which come to settle. The Thomisus 
tigrinus is very common on the stems of trees. Clerk has 
seen the Thomisus cristatus , which he preserved in a box, 
make at one of its angles a little web as thin as paper. It 
appears, however, certain, according to the observations of 
other naturalists, that the Thomisi do not weave nets for the 
purpose of surprizing their prey, which they take by running, 
or they wait patiently until it imprudently approaches within 
their reach. M. Walckenaer tells us that they introduce 
