FOOD OF INSECTS. 229 
machinery so complex? One probable reason is, that it was necessary for 
drying the gum sufficiently to form a tenacious line, that an extensive sur- 
face should be exposed to the air, which is admirably effected by dividing 
it at its exit from the abdomen into such numerous threads. But the chief 
cause, perhaps, is the occasion (hereafter to be adverted to) which the 
spider sometimes has to employ its threads in their finer and unconnected 
state before they unite to forma single one. The spider is gitted by her 
Creator with the power of closing the orifices of the spinners at pleasure, 
and can thus, in dropping from a height by her line, stop her progress at 
any point of her descent ; and, according to Lister!, she is also able to 
retract her threads within the abdomen ; but this is doubted, and with 
apparent reason, by De Geer.? 
The only other instruments employed by the spider in weaving are her 
feet, with the claws of which she usually guides, or keeps separated into 
two or more, the line from behind ; and in many species these are admirably 
adapted for the purpose, two of them being furnished underneath with teeth 
like those of a comb, by means of which the threads are kept asunder. 
But another instrument was wanting. The spider, in ascending the line 
by which she has dropped herself from an eminence, winds up the superfluous 
cord into a ball. In performing this the pectinated claws would not have 
been suitable. She is therefore furnished with a third claw between the 
other two’, and is thus provided for every occasion. 
The situations in which spiders place their nests are as various as their 
construction. Some prefer the open air, and suspend them in the midst of 
shrubs or plants most frequented by flies and other small insects, fixing 
them in a horizontal, a vertical, or an oblique direction. Others select the 
corners of windows and of rooms, where prey always abounds; while many 
establish themselves in stables and neglected out-houses, and even in 
cellars and desolate places in which one would scarcely expect a fly to be 
caught ina month. It is with the operations of these last especially that 
we are accustomed to associate the ideas of neglect and desertion by man 
—associations which, both in painting and allegory, have been often happily 
applied. Hogarth, when he wished to produce a speaking picture of 
neglected charity, clothed the poor’s box in one of his pieces with a spider's 
net; and the Jews, in one of the fables with which they have disfigured 
the records of Holy Writ, have not less ingeniously availed themselves of 
the same idea, They relate that the reason why Saul did not discover 
David and his men in the cave of Adullam* was, that God had sent a 
spider which had quickly woven a web across the entrance of the cave in 
which they were concealed ; which being observed by Saul, he thought it 
useless to investigate further a spot bearing such evident proofs of the 
absence of any human being. 
The most incurious observer must have remarked the great difference 
which exists in the construction of spiders’ webs. Those which we most 
1 Hist, Anim. Ang. p. 8. 
2 De Geer, vii. 189, Mr, Blackwall has explained that this apparent retraction 
Which is chiefly perceptible in the line forming the concentric circles of the geo- 
Metric spiders, is an optical illusion, depending upon its extreme elasticity, which 
admits of its being extended several inches and of contracting again into a minute 
globule, (Zool. Journ. vy. 187.) 
F Leeuw. Opuse. iii, 317. f, 1. 
1 Sam. xxiv, 4. 5 Lesser, 1. ii, 291, 
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