ON THE NETS OF GEOMETRIC SPIDERS. 285 
thoroughly satisfied myself, by observation and ex- 
periment, that in such instances spiders invariably 
avail themselves of currents of air, by which their 
lines are sometimes conveyed to a surprising 
distance. 
If the Geometric Spiders be placed on twigs or 
metallic rods set upright in glazed earthenware ves- 
sels with perpendicular sides, containing a sufficient 
quantity of water completely to immerse their bases, 
the spiders, thus insulated, use every means in their 
power to effect an escape; all their efforts, however, 
uniformly prove unavailing in a still atmosphere ; 
nevertheless, when exposed to a current of air, or 
when gently blown upon with the’ breath, they im- 
mediately turn the abdomen in the direction of the 
breeze, and emit from the spinning-apparatus some 
of their liquid gum, which, being carried out in a 
line by the current, becomes connected with some 
object in the vicinity. This the spider ascertains by 
pulling it with her feet, and, drawing it in till it is 
sufficiently tense, she gums it fast to the twig or 
rod, and, passing along it, speedily regains her 
liberty. Now, that the same means are frequently 
resorted to by spiders in their natural haunts, for the 
purposes of changing their situation and fixing the 
foundations of their snares, I have repeatedly ob- 
served. I am aware that, in the ‘Introduction to 
Entomology,’ an objection has been urged against the 
explanation of the difficulty here insisted upon. 
