SPIDERS' EGGS AND THEIR ENVELOPES. 135 



than her body, with which, on alarm, she makes off with all 

 possible expedition. These balls, popularly known as Spiders' 

 eggs, are in fact made up of a numerous group of them, 

 enclosed within a woven envelope ; and the way in which 

 these spinning mothers proceed to 



" tie" their " treasure up in silken bags," 



is another very curious exercise of their weaving art. Using 

 her own body (after the manner of a nest-building bird) as a 

 measure for its circumference, the spider spins, first, the lower 

 half of her intended covering, which in this stage of its pro- 

 gress resembles a cup or nest. She then proceeds to lay her 

 eggs, and over these, when piled up within, weaves a convex 

 cover which, united with the receptacle at bottom, renders 

 the ball complete. These silken egg-purses vary in colour ; 

 those of the House-spiders being white, of the common 

 Garden yellow, of other out-door species blue or greenish. 



In form they are usually globular, but variations from this 

 shape are occasionally met with. Last summer we noticed an 

 exceedingly pretty one in the instance of a small greenish 

 Spider, variegated with white, of which we found many on 

 the leaves of a wall plum tree, keeping watch and ward over 

 their nests. These, which were attached to the under side of 

 the leaf, were white, and of an elegant urn-like shape, some- 

 thing resembling the seed-case of a poppy. Bound the circum- 

 ference of the top or cover, were five, and in other specimens, 

 seven points, another rising pyramidically from its centre. 



