FOOD OF INSECTS. 



341 



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 form a single one. 

 The spider is gifted 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 pro- 

 vided for every occasion. 



The situations in which spiders place their nests are as 

 various as their construction. Some prefer the open air, and 

 susjDcnd 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 in a month. It is with the 



1 Hist. Ajiim. Ang. p. 8. 



2 De Geer, vii. 189. Mr. Blackvvall has explained that this apparent re- 

 traction, which is chiefly peiceptible in the line forming the concentric circles of 

 the geometric spiders, is an optical illusion, depending on its extreme elasticity, 

 which admits of its being extended several inches and of contracting again into a 

 minute globule. {Zool. Journ. v. 187.) 



3 Leeuw. Opusc. iii. 317. f. 1. 



z 3 



