FOOD OF INSECTS. 233 
In the above description, which is from my own observations, I have 
supposed the spider to fix the first and main line of her net to points from 
one of which she could readily climb to the other, dragging it after her ; 
and many of these nets are placed in situations where this is very prac- 
ticable. They are frequently, however, stretched in places where it is 
quite impossible for the spider thus to convey her main line—between the 
branches of lofty trees having no connection with each other; between 
two distinct and elevated buildings; and even between plants growing in 
water. Here then a difficulty occurs. How does the spider contrive to 
extend her main line, which is often many feet in length, across inaccessible 
openings of this description ? 
With the view of deciding this question, to which I could find no very 
satisfactory answer in books, I made an experiment, for the idea of which 
I am indebted to a similar one recorded by Mr. Knight', who informs us 
that if a spider be placed upon an upright stick having its bottom immersed 
in water, it will, after trying in vain all other modes of escape, dart out 
numerous fine threads so light as to float in the air, some one of which, 
attaching itself to a neighbouring object, furnishes a bridge for its escape. 
It was clear that if this mode is pursued by the geometric spiders, it 
would go considerably towards furnishing a solution of the difficulty in 
question. I accordingly placed the large diadem spider (Zpeira Diadema) 
upon a stick about a foot long, set upright in a vessel containing water. 
After fastening its thread (as all spiders do before they move) at the top 
of the stick, it crept down the side until it felt the water with its fore feet, 
which seem to serve as antenne: it then immediately swung itself from 
the stick (which was slightly bent) and climbed up by the thread to 
the top. This it repeated perhaps a score times, sometimes creeping 
down a different part of the stick, but more frequently down the very side 
it had so often traversed in vain. Wearied with this sameness in its ope- 
rations, I left the room for some hours. On my return I was surprised 
to find my prisoner escaped, and not a little pleased to discover, on further 
examination, a thread extended from the top of the stick to a cabinet 
or other shelter, and there construct a cell in which the spider remains concealed 
till the vibrations of a strong line of communication, composed of several united 
threads, which she has spun from the centre of the net to her cell, inform her of the 
capture of a fly, to which she then rushes along this bridge. This criticism as to 
the too extensive generalisation of the procedures of the garden spider above de- 
scribed is perfectly just, as my own observations since the publication of the last 
edition of this work, but long before I had seen Mr, Blackwall’s paper, had shown 
me, My excuse must be that the observations above recorded (which are left pre- 
cisely as originally written about the year rad having been made on the spur of 
the occasion in my garden at Drypool, near Hull, when to my surprise I could not 
find in books any intelligible account of the way in which the geometric spiders 
construct their nets, were necessarily confined to the common garden species alone 
found there, and my attention having been subsequently fully occupied in other 
directions, it did not occur to me that probably the operations of other species might 
differ from those 1 had witnessed. ‘These variations, however, do not affect the 
accuracy of the description above given of the procedures of the species referred to, 
one of the commonest of the tribe, which description also, except in the two parti- 
culars above stated, is generally applicable to the whole geometric race, and has 
been in great part adopted by Mr. Blackwall in his more full detail of their 
Operations. 
! Treatise on the Apple and Pear, p. 97, 
