Structure and Economy of Spiders. 475 



it can seldom be seen to advantage, unless artificial light be 

 employed, some skill in the management of which is required 

 in order to avoid disturbing the spider. The modus operaiidi, 

 as nearly as I can ascertain it by the most diligent observation, 

 appears to be this. The points of the lower row of spines are 

 protruded between those of the upper row, and in passing across 

 the extremities of the mammuloe comb out the tortuous lines, 

 which run into numerous flexures in consequence of not being 

 kept fully extended. The purpose subserved by the upper row 

 of spines seems to be the extrication of the tortuous lines from 

 the spines of the lower row, by a slight motion outwards, which 

 disengages their points. Now, were the blue bands glutinous, 

 this mode of proceeding would be quite unavailing ; it is only 

 on the supposition, therefore, that they have a fibrous structure, 

 that their adhesive property can be satisfactorily explained. 

 When a sufliicient quantity of the inflected filaments is produced, 

 the spider again applies its spinners to one of the glossy lines, 

 and attaches the flocculus to it. In this manner it proceeds 

 with its labours, occasionally employing the combing apparatus 

 of both hind-legs, till the web is completed. Should any of the 

 flocculi be destroyed, or rendered almost useless by having their 

 adhesive property impaired, new ones are constantly added to 

 the snare. 



A more exact idea of the mechanism of the combing appara- 

 tus than can be conveyed in words, will be obtained by inspect- 

 ing the accompanying plate (Tab. XXXI.). 



Naturalists appear to concur in the opinion, that the tarsi of 

 spiders are armed at their extremities with three claws, which 

 occupy the upper and anterior portion of the foot. That this is 

 the case with some species cannot be denied ; other species, how- 

 ever, belonging to various genera, My gale avicularia,Drassus me- 



lanogaster. 



