SPIDERS, SCORPIONS, AND MITES. 



189 



surface, collects another air-bubble, which she adds to the 

 former. "When she has, in this manner, sufficiently en- 

 larged her balloon of air, she encloses it with silk of extreme 

 whiteness. Within this balloon, w T hich is open below, she 

 then sits in a reversed position. She then stretches through 

 the water irregular threads, which converge to her habi- 

 tation, and which arrest minute water-mites and other 

 insects. These are seized, and carried within doors to be 

 eaten, but sometimes the prey is borne to the surface, and 

 devoured on the bank."'" 



The accuracy of these observations has been recently 

 confirmed by Professor Bell. 



Among the largest and best known of our native species 

 is the handsome Garden Spider [Epeira diadema). Its 

 form is familiar to every one in the latter part of summer 

 and autumn, its plump abdomen gray or fawn colour, 

 elegantly spotted with white, and its legs widely extended, 

 as it hangs head downward on its perpendicular web, 

 which is formed of concentric circles of fine thread, on a 

 frame-work of radiating lines. This geometric web is a 

 beautiful example of an insect-manufacture. Having 

 formed the foundation of her net and drawn the skeleton 

 of it, by spinning a number of rays converging to the 

 centre, she next proceeds, setting out from that point, to 

 spin a spiral line of unadhesive thread, like that of the rays 

 which it intersects, and to which she attaches it, and, 

 after numerous circumvolutions, finishes it at the circum- 

 ference. This line, together w 7 ith the rays, serves as a 

 scaffolding to walk over, and it also keeps the rays pro- 

 perly stretched. Her next labour is to spin a spiral line 



* Aptere, ii. 383. 



