ARANEINA. 645 



sucli as the Autbrobia Mammotbia of Tellkampf from Mam- 

 moth Cave, and other spiders inhabiting European caves, there 

 are none. 



"We quote an interesting account of the habits of spiders, 

 especially the mode of spinning their webs, published by Mr. 

 J. H. Emertou in the "American Naturalist" (ii, p. 478), who 

 has studied our native species with much care. 



" The feet of spiders are wonderfully adapted for walking ou 

 the web. Each foot is furnished with three claws (Plate 12, 

 Fig. 6, a, b, &),the middle one of which (a) is bent over at the 

 end, forming a long finger for clinging to the web, or for guid- 

 ing the thread in spinning. The outer claws (e, e) are curved 

 and toothed like a comb. Opposite the claws are several stiff 

 hairs (c) which are toothed like the claws, and serve as a 

 thumb for the latter to shut against." 



"When a spider wishes to build a web she usually selects a 

 corner, so that the structure may be attached on several sides. 

 She then runs a few threads along the objects to which the web 

 is fastened, to facilitate her passage from point to point. The 

 web is commenced by a line or two across the point where the 

 centre is to be, which is not usually the geometric centre, but 

 nearer the top than the bottom. Radiating lines (Plate 12, fig. 

 1, 6, &, h) are then spun from the centre in all directions. In 

 doing this the spider often crosses from one side of the web 

 to the opposite, so that the finished portion is alwa3-s tightly 

 drawn, and the tension of the completed web is the same in 

 every part." 



" Having finished the framework, the spider begins near the 

 centre and spins a thread (Fig. 1, c, c, c) spirally, around 

 the web to the circumference, fastening it to each radius as it 

 crosses. The distance between the spirals varies with the size 

 of the spiders, being about as far as they can reach. This 

 spiral thread serves to keep the parts of the web in place dur- 

 ing the rest of the process, and is removed as fast as the web 

 is finished. It also furnishes a ready means of crossing from 

 one radius to another where the}- are farthest apart. All the 

 thread spun up to this stage of the process is smooth when 

 dry, and will not adhere if touched with a smooth object." 



"The spider, having thus formed the web, begins to put in 



