ON AERON AUTIC SPIDERS. 271 
case with some of the more common species, with 
Tegenaria civilis and Ciniflo atrox for example, I take 
this opportunity of calling the attention of observers 
to the fact, which, if unnoticed, might occasion them 
some disappointment. 
In conducting experiments similar to those de- 
scribed above, it will be very apparent that there is a 
decided advantage in employing, as I have recom- 
mended, vessels having smooth, perpendicular sides, 
care being taken not to fill them with water, for 
several kinds of spiders run upon that liquid with 
greater facility than they do on land; and though 
most of our larger indigenous species are, at least 
when they have attained their full growth, quite 
incapable of walking upon its surface, still they some- 
times contrive to effect a passage over it by the fol- 
lowing ingenious expedient. Placed on an insulated 
twig, they attach a line to it which they seize with 
the foot of one of the hind legs, allowing it to run 
freely through the claws as it proceeds from the 
spinners. Descending to the surface of the water, 
they use their best exertions to pass over it; and 
should a little dust or other extraneous matter hap- 
pen to rest upon it, enabling them to obtain even a 
slight footing, their efforts are frequently attended 
with success, the line, which chiefly contributes to 
support them during their progress and also serves 
to secure a return to the twig should their attempts 
prove abortive, being ultimately made fast to the 
