xin] SPINNING APPARATUS AND FEET 117 



silkworms in the same box with mulberry leaves, but 

 spiders require separate compartments or they will 

 fight and devour each other, and the provision of 

 suitable food for them is such a troublesome matter 

 that it has proved quite impracticable on a commercial 

 scale. 



We have incidentally seen that there are quite a 

 number of different operations in which the spinning 

 apparatus takes part. There is the line which most 

 spiders lay down as they wander, and which secures 

 them from the danger of a fall if they lose their foot- 

 ing ; there is the snare for catching prey, the nest or 

 retreat, and the egg-cocoon, and in addition, silk from 

 the spinnerets may be used to enwrap and paralyse 

 captured insects, or to assist the young spider to 

 migrate. Since the Epeiridae perform all these 

 operations, and are, moreover, the most finished of 

 snare-makers, it does not surprise us to find in them 

 the highest development of the silk glands and the 

 most complete battery of spools and spigots on the 

 spinnerets. Many spiders, as we know, make no snare 

 at all, and in the case of some, very little spinning is 

 attempted beyond the manufacture of a rather rudi- 

 mentary covering for the eggs. Naturally a less 

 complex spinning apparatus is required, and we 

 accordingly find that jumping spiders, for instance, 

 have only about fifty silk-glands comprising three 

 different kinds of gland, while the glands found in 



