3492 MOTIONS OF INSECTS. 
with which they are always as it were strung, are a se- 
condary object with them? So prodigious are their 
numbers, that sometimes every stalk of straw in the stub- 
bles, and every clod and stone in the fallows, swarms 
with them. Dr. Strack assures us that twenty or thirty 
often sit upon a single straw, and that he collected about 
2000 in half an hour, and could have easily doubled the 
number had he wished it: he remarks, that the cause of 
their escaping the notice of other observers, is their fall- 
ing to the ground upon the least alarm. 
As to what becomes of this immense carpeting of 
web there are different opinions. Mr. White conjec- 
tures that these threads, when first shot, might be en- 
tangled in the rising dew, and so drawn up, spiders and 
all, by a brisk evaporation, into the region where the 
clouds are formed*. But this seems almost as inadmis- 
sible as that of Hooke, before related. An ingenious 
and observant friend, thinking the numbers of the flying 
spiders not sufficient to produce the whole of the phe- 
nomenon in question, is of opinion that an equinoctial 
gale, sweeving along the fallows and stubbles coated with 
the gossamer, must bring many single threads into con- 
tact, which, adhering together, may gradually collect 
into flakes; and that being at length detached by the 
violence of the wind, they are carried along with it: and 
as it is known that such winds often convey even sand and 
earth to great heights, he deems it highly probable that 
so light a substance may be transported to so great an 
elevation, as not to fall to the earth for some days after, 
when the weather has become serene, or to descend upon 
4 Nat. Hist. i, 326. 
