"A Young Inquirer" asks what is the cause of that appearance so
often met with in the autumn, resembling spider-webs. He says, if
it be the production of that insect, how do you account for their
hanging apparently unsuspended in the air, as it is seen fifty or
sixty feet high, without a tree or any other object near to which
it could be attached?
I suppose you have not time to give to such questions minutely, as
your reply would lead one to infer that Gossamer proceeded from
spiders in general; and if it be meant that all true spiders spin,
it is no doubt correct; but the Gossamer which "A Young Inquirer"
asks about is the production of a small black spider about the
size of a flea, which was a true aeronaut long before Montgolfier
or Lunardi, and if "A Young Inquirer" has access to either the
"Linnean Transactions" or the first series of Loudon's "Magazine
of Natural History," he will find particulars in the latter,
showing that a violent controversy raged through the three first
volumes between Mr. Blackwall and Dr. Murray on the question
whether the ascent of this spider (_A. AEronautica_) was electric,
or whether it merely travelled in the direction of the wind. But
if "A Young Inquirer" would deserve his name, let him begin with
these spiders and observe for himself; he will find the inquiry
highly interesting.
He has no doubt frequently seen a small black spider creeping on
his hat or clothes (if he lives in the country this must have
occurred to him many times); this is the aeronautic spider. Let
him take this upon his hand, and if he be in the house let him
carry it to the open door or window, and allow it to creep up to
the tip of his finger, which he must then hold in a horizontal
position. When the spider finds it can proceed no further by
creeping, it generally drops a few inches, where it remains
suspended for a short time, apparently quite still, but if very
closely observed another thread (Gossamer) may be seen proceeding
from its vent, and when this has reached the length which the
spider's instinct tells it is sufficient for the purpose, it cuts
off the connection till then existing between it and the thread by
which it has hitherto been suspended from the finger, and floats
away into space. Very often it rises almost vertically, sometimes
its course is nearly horizontal, and sometimes it is oblique.
I cannot say, as Mr. Murray does, that I have seen the spider go
_against_ the wind, neither can I confirm Mr. Blackwall's
assertions that he always goes right before the wind, for I have
seen him go apparently across the current, so far as I could judge
of the direction of the wind at the time.
If "A Young Inquirer" makes the experiment I have suggested, let
him not be discouraged if the first he tries does not go off at
all, as I have sometimes found this to be the case, which I
accounted for by supposing that possibly the supply of materials
might be exhausted at the time.
I do not remember that I ever saw one of these aeronautic spiders
preying upon any insect, yet it must be for some such purpose that
they ascend to great altitudes, sometimes in countless numbers,
and the way they come down again is quite as curious as the manner
in which they ascend.
Many years since, as I was walking over the hills in the
neighbourhood of Blackburn, on a bright, still morning in
September, thousands of small locks of what looked like cotton
wool were slowly descending to the ground from various altitudes--
some as high as I could see--and tens of thousands of similar
locks were lying on the ground on both sides of the path by which
I was travelling; and on examination I found that all these locks
were Gossamer, some with the spider still with them, but generally
deserted. The spiders when they wanted to come down, finding there
was no descending current of air, or perhaps, as Mr. Murray says,
no electricity, determined to descend in _parachutes_; they
therefore had drawn up their cables hand over hand (as they may
often be seen to do when they wish to ascend their own lines)
until they accumulated a mass heavy enough to fall by its own
weight, and carry them along with it.
I have seen Gossamer in this form at other times before and since,
but in the likeness of a snow-shower I never saw it except on that
occasion, and, if I recollect aright, the same enormous shower of
Gossamer was observed to extend as far as Liverpool.
What induced these millions of spiders to go up at the same time,
of course I do not know, and can only suppose that they went up to
feed; but, as I have said previously, I never saw one of this
species preying upon anything. The idea that they go aloft to kill
the _Furia Infernalis_ is too fanciful to deserve credit. Who
knows whether the _Furia Infernalis_ is anything else than a
murderous Mrs. Harris--at all events, who has seen one, and what
was it like?
I suppose they are true sportsmen, and disdaining to take their
fish in nets, they, like thorough brothers of the angle, fish only
_with fine gut_.
Gilbert White noticed one of these showers of Gossamer, and as his
account is very interesting, I quote it. He says that on the 21st
of September, 1741, intent upon field diversions, he rose before
daybreak, but on going out he found the whole face of the country
covered with a thick coat of cobweb drenched with dew, as if two
or three setting-nets had been drawn one over the other. When his
dogs attempted to hunt, their eyes were blinded and hoodwinked, so
much that they were obliged to lie down and scrape themselves.
This appearance was followed by a most lovely day. About 9 A.M. a
shower of these webs (formed not of single threads, but of perfect
flakes, some near an inch broad and five or six long) was observed
falling from very elevated regions, which continued without
interruption during the whole of the day, and they fell with a
velocity which showed they were considerably heavier than the
atmosphere. When the most elevated station in the country where
this was observed was ascended, the webs were still to be seen
descending from above, and twinkling like stars in the sun, so as
to draw the attention of the most incurious. The flakes of the web
on this occasion hung so thick upon the hedges and trees, that
basketsful might have been collected. No one doubts (he observes)
but that these webs are the production of small spiders.
These aerial spiders are of two sizes, although of the same colour
and general appearance; they are probably male and female. At all
events they do not vary in size more than other species of spiders
when the sexes differ.
Has it been observed by naturalists that spiders eat their own
webs? A large one that I used to feed when I was a lad with wasps,
humble bees, and flesh-flies, used to do so occasionally. These
insects were so strong that they often ruined the web in their
efforts to escape, and the spider, quite aware of the rough
customers it had to deal with, would often coil a cable of many
folds round them before venturing to seize them with its
mandibles. It would, if the web was ruined by the struggles of the
insect, deliberately gorge it, which I accounted for by supposing
that unless it did so it would not be able to secrete a sufficient
supply of material to enable it to spin another.
The leaping spiders are another curious species, which construct
no webs, although they spin threads. This spider may be seen
frequently on the walls of houses, and if carefully watched it
will be seen to range up and down in quest of small gnats and
other insects; when it observes one it creeps to within about two
inches of it, and backing slightly, it appears to hesitate for a
moment, and then springs upon the fly, but always before doing so
it fixes a thread to the spot from whence it springs, so that if
the fly happens to be too strong for it, and is able to detach
itself from the wall, they both remain suspended from the thread
which has been previously fixed by the spider. This I have seen
more than once.
They sometimes venture on larger game than the small gnats. One I
was watching one day came upon one of the large _Ephemera_ (the
Browndrake), an insect ten times as large as the spider, but after
many points (for the setting of the spider before it springs is
very similar in manner to that of a thoroughbred pointer [17]), in
which it kept varying its position, apparently to gain some
advantage, it gave up the attempt, discretion proving the better
part of valour.
When botanizing on Erris Begh (in Connemara), this summer, I
passed through many spider-lines so strong as to offer a very
sensible resistance before breaking. I don't remember to have ever
before met with them so strong and tenacious, and the makers of
optical instruments might there have found abundance of threads
which I am told are valuable as _cross-wires_ for transit-
instruments and theodolites. I did not meet with any of the
spiders that had thrown out these lines, but judging of them by
their works I suppose they must have been large ones.
One of your correspondents was inquiring a few weeks since how it
was that a spider could throw out a long line between two trees or
buildings at a considerable distance from each other. This seems
to me to be very easily explained, if we reason from the analogy
of the flying spider. The spider seems to throw out a line,
trusting it will catch somewhere or other, and it is able to
ascertain it has done so by pulling at it, and when it finds that
it is firmly fixed it starts off to travel upon it, as I have
occasionally noticed.
Everyone has noticed how carefully the spider carries her cocoon
of eggs attached to the vent, and how disconsolate she appears to
be when deprived of them; but I don't think it is so generally
known that some of the spiders carry their young on their backs
for some time after they are hatched. I remember seeing an
instance of this one day when on the Moors, grouse-shooting. I saw
what seemed to be a very curious insect travelling on the ling
(heather), and on stooping down to examine it I found it was a
large spider, upon the back of which (in fact, all over it) were
clustered some dozens of young ones, about the size of pins'
heads; she also seemed to guard them with great care, and seemed
much afraid of losing them.