ON ARACHNIDA. 467 



occupy the angles. Their surface forms a triangular plane, 

 but which becomes a little concave in consequence of the 

 natural sinking in of the web. Its threads are very close, cross 

 each other, and being strongly bound together by their 

 viscosity, give it some resemblance to a very fine stuff, but 

 which can, nevertheless, retain the various insects which 

 come there, on whicli these animals feed, and frequently even 

 coleoptera of tolerable size. Many loose, and as it were, 

 floating threads, compared by Lister to cordages, or sail-yards 

 of vessels, are placed on the upper side of the web, and 

 become sorts of snai'es for the insects which get embarrassed 

 there. Immediately at the angle formed by the union of the 

 two walls, the spider weaves a cylindrical tube, having one of 

 its apertures above, the other underneath. It there remains 

 constantly in ambush, the head being turned forwards ; as 

 soon as a fly, or any other little animal is arrested in the web, 

 it runs forward, promjjtly seizes its prey, and drags it to the 

 bottom of its lodge, for the purpose of sucking it with the 

 greater facility. If any pressing danger should frighten the 

 spider, it takes to flight, and speedily escapes through the 

 lower aperture of its habitation. Romberg has also described, 

 in the memoirs of the Academy of Sciences, 1707, the man- 

 ner in which these animals manage in spreading their webs. 

 The cavities which are found under stones, in rubbish, also 

 serve them for the purpose of retreat. Lister has occasionally 

 encountered them in the woods. He has seen the male and 

 female on the same web, in the commencement of June, the 

 season of their amours. Having thrown some flies to them, 

 each individual took one. The laying takes place towards 

 the end of the following month. The cocoon has a double 

 envelope of very white silk. It is placed near the anterior 

 aperture of the tube where the spider remains, and it seems to 

 form a portion of the web. The eggs are whitish, and have 

 no adherence. Audebert brought up, and kept for some 



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