344 ARACHNIDA—ARANEAE CHAP, 
The silk is utilised in many ways, serving for the construc- 
tion of snares, nests, and cocoons, as well as for enwrapping the 
captured prey, and for anchoring the spider to a spot to which 
it may wish to return. 
Spiders may be roughly distinguished as sedentary or vagabond, 
the former constructing snares, and the latter chasing their prey 
in the open. We will first consider the various forms of snare, 
beginning with that characteristic of the Epeiridae. 
The Circular Snare.—This familiar object, sometimes spoken 
of as the orb-web or wheel-web, is always the work of some 
spider of the Family Epeiridae. 
The accuracy and regularity of form exhibited by these snares 
has caused their architects to be sometimes called the geometric 
spiders. The ingenuity displayed by them has always excited 
the admiration of the naturalist, and this is increased on closer 
observation, for the snares are in reality even more complex than 
they appear at first sight. 
The first care of the spider is to lay down the foundation 
threads which are to form the boundary lines of its net. If the 
animal can reach the necessary points of attachment by walking 
along intervening surfaces the matter is comparatively simple. 
The spinnerets are separated and rubbed against one of the points 
selected, and the spider walks away, trailing behind it a thread 
which it keeps free from neighbouring objects by the action of 
one of its hind legs. On reaching another desirable point of 
attachment the line is made taut and fixed by again rubbing 
the spinnerets against it. By a repetition of this proceeding a 
framework is presently constructed, within which the wheel or 
orb will ultimately be formed. 
The process of fixing and drawing out a line can be con- 
veniently watched in the case of a Spider imprisoned in a glass 
vessel, and it will be seen, by the aid of a lens, that a large 
number of very fine lines starting from the point of attachment 
seem to merge into a single line as the Spider moves away. ‘This 
has given rise to the prevalent and very natural idea that the 
ordinary spider’s line is formed or “woven” of many strands. 
This, however, is not the case,’ for the fine attachment-lines are 
not continued into the main thread, but only serve to anchor it 
to.the starting-point. 
7 Warburton, @ J. Mier. Sci. xxi., 1890, p. 29. 
