12(3 
THE ENTOMOLOGIST’S WEEKLY INTELLIGENCER. 
the hope that some one will be induced 
to reply to a portion of this, and that 
I shall have the pleasure of returning 
to the subject again on some future 
day. 
John Scott. 
13, Torrington Villas, Lee, S.E.; 
January 9, 1861. 
RAY SOCIETY’S PUBLICATIONS. 
Extracts from Mr. Blackwall's Volume on 
British Spiders. 
(Continued from p. 119.) 
“ Dr. Lister supposed that spiders are 
able to retract the lines they spin within 
the abdomen, and whoever minutely ob- 
serves the Epeirce, when fabricating their 
snares, will almost be induced to enter- 
tain the same opinion. The viscid line 
produced by these spiders in their transit 
from one radius to another, is sometimes 
drawn out to a much greater extent than 
is necessary to connect the two, yet on 
approaching the point to which it is to 
he attached, it appears to re-enter the 
spinners, till it is reduced to the exact 
length required. This optical illusion, 
for such it is, is occasioned by the ex- 
treme elasticity of the line, which may 
be extended greatly by the application 
of a slight force, and on its removal will 
contract proportionally. By this pro- 
perty the viscid, spiral line is accommo- 
dated to the frequent and rapid changes 
in distance which take place among the 
radii when agitated by winds or other 
disturbing forces, and by it insects, which 
fly against the snare, are more completely 
entangled than they otherwise could be 
without doing extensive injury to its 
framework. 
“ Complicated as the processes are by 
which these symmetrical nets are pro- 
duced, nevertheless young spiders, acting 
under the influence of instinctive im- 
pulse, display, even in their first attempts 
to fabricate them, as consummate skill 
as the most experienced individuals. By 
contributing to check the too rapid multi- 
plication of insects, from which they 
chiefly derive their sustenance, spiders 
perform an important part in the eco- 
nomy of nature. They devour one 
another also, the weaker falling victims 
to the more powerful; and as female 
spiders, with few exceptions, are larger 
and more vigorous than males, they fre- 
quently prey upon the latter, sometimes 
immediately after they have received their 
embraces. Their enemies, however, are 
not limited to those of their own kind ; 
quadrupeds, birds, fishes, reptiles and 
even insects, destroy them in large num- 
bers. 
“ Although spiders are not provided 
with wings, and consequently are incap- 
able of flying, in the strict sense of the 
word, yet, by the aid of their silken fila- 
ments, numerous species, belonging to 
various genera, are enabled to accom- 
plish distant journeys through the atmo- 
sphere. These aerial excursions, which 
appear to result from an instinctive desire 
to migrate, are undertaken when the 
weather is bright and serene, particularly 
in autumn, both by adult and immature 
individuals, and are effected in the fol- 
lowing manner. After climbing to the 
summits of different objects, they raise 
themselves still higher by straightening 
the limbs ; then elevating the abdomen, 
by bringing it from the usual horizontal 
position into one almost perpendicular, 
they emit from the spinners a small 
quantity of viscid fluid, which is drawn 
out into fine lines by the ascending cur- 
