ARANEA AQUATICA. 37 1 
which its web is composed, dries very 
gradually; and as this clammy quality 
assists in catching those flies, which other- 
wise might force themselves through, the 
sagacious animal daily renews such of 
the circular threads as are best adapted 
to that purpose. 
Lucy, And I suppose the radii are 
not renewed, because their chief use is to 
keep the web steady ? 
Mother, Just so ; the aranea aqua^ 
tica *, or water spider, is another remark^ 
able species, and is found in most parts of 
Europe, It lives at the bottom of fresh 
waters, where it has the brilliant appear- 
ance of silver ; but this effect is produced 
by a bubble of air, in which it is enr 
closed. 
Lucy, I suppose, mamma, that, like 
the fan-tailed larvae, it cannot live under 
water without a provision of air; but 
how does it manage to confine the air 
there ? 
I... V..* Plate XXIV. 
