Facts and Thoughts about Spiders. 183 
roughly shaken, is to drop itself down on the earth, 
where it lies simulating death. In falling, it drops 
just as a green leaf would drop, that is, not quite so 
rapidly as a round, solid body like a beetle or 
spider. Kowin the bushes there is another Epei'ra, 
in size and form like the last, but diflPering in colour; 
for instead of a vivid green, it is of a faded yellowish 
white — the exact hue of a dead, dried-up leaf. This 
spider, when it lets itself drop — for it has the same 
protective habit as the other — falls not so rapidly 
as a green freshly broken off leaf or as the green 
spider would fall, but with a slower motion, precisely 
like a leaf withered up till it has become almost 
Imht as a feather. It is not difficult to imagine how 
this comes about : either a thicker line, or a greater 
stiffness or tenacity of the viscid fluid composing 
the web and attached to the point the spider drops 
from, causes one to fall slower than the other. But 
how many tentative variations in the stiffness of the 
web material must there have been before the precise 
degree was attained enabling the two distinct species, 
differing in colour, to complete their resemblance to 
falling leaves— a fresh green leaf in one case and a 
dead, withered leaf in the other ! 
The Tetragnatha — a genus of the Epeira family, 
and known also in England — are small spiders 
found on the margin of streams. Their bodies are 
slender, oblong, and resembling a canoe in shape ; 
and when they sit lengthwise on a stem or blade of 
grass, their long, hair-like legs arranged straight 
before and behind them, it is difficult to detect 
them, so closely do they resemble a discoloured 
stripe on the herbage. A species of Tetragnatha 
