It is well known that most of the British spiders, when a large insect
is caught in their webs, endeavour to cut the lines and liberate their
prey, to save their nets from being entirely spoiled. I once, however,
saw in a hothouse in Shropshire a large female wasp caught in the
irregular web of a quite small spider; and this spider, instead of
cutting the web, most perseveringly continued to entangle the body, and
especially the wings, of its prey. The wasp at first aimed in vain
repeated thrusts with its sting at its little antagonist. Pitying the
wasp, after allowing it to struggle for more than an hour, I killed it
and put it back into the web. The spider soon returned; and an hour
afterwards I was much surprised to find it with its jaws buried in the
orifice, through which the sting is protruded by the living wasp. I
drove the spider away two or three times, but for the next twenty-four
hours I always found it again sucking at the same place. The spider
became much distended by the juices of its prey, which was many times
larger than itself.
I may here just mention, that I found, near St. Fe Bajada, many large
black spiders, with ruby-coloured marks on their backs, having
gregarious habits. The webs were placed vertically, as is invariably
the case with the genus Epeira: they were separated from each other by
a space of about two feet, but were all attached to certain common
lines, which were of great length, and extended to all parts of the
community. In this manner the tops of some large bushes were
encompassed by the united nets. Azara [10] has described a gregarious
spider in Paraguay, which Walckanaer thinks must be a Theridion, but
probably it is an Epeira, and perhaps even the same species with mine.
I cannot, however, recollect seeing a central nest as large as a hat,
in which, during autumn, when the spiders die, Azara says the eggs are
deposited. As all the spiders which I saw were of the same size, they
must have been nearly of the same age. This gregarious habit, in so
typical a genus as Epeira, among insects, which are so bloodthirsty and
solitary that even the two sexes attack each other, is a very singular
fact.
In a lofty valley of the Cordillera, near Mendoza, I found another
spider with a singularly-formed web. Strong lines radiated in a
vertical plane from a common centre, where the insect had its station;
but only two of the rays were connected by a symmetrical mesh-work; so
that the net, instead of being, as is generally the case, circular,
36