104 



ARANEIUA OK SPIDERS. 



web consists of two substances — one forming the solid elastic 

 thread, the other forming the little globules. There is a popular 

 idea that the spider can withdraw its web into its body again : 

 this is not correct. When once hardened, the web always 

 remains so. In the spider's web, the viscid globular glue on the 

 web is distributed only over certain areas : passages are left, so 

 that the spider can walk along the web without coming in 

 contact with the sticky substance. This substance is for catch- 

 iag and retaining the insects that fly into the web. In some 

 spiders this webbing is formed for taking aerial flights. The so- 

 called " gossamer " web is formed by strands of fine silk blowing 



-Q^ 



-a- 



Fig. 40. — Orb-weaving Spider, Etc. 

 A, Epeira diademata : E, Drassus BlackwallU ; c, thread ot Epeira yreb, 



about and adhering together, thus forming the white flaky 

 masses. Some spiders may be found on these threads as they 

 are being wafted about — the spider having, as it were, taken 

 advantage of this mode of transit. 



There are two chief divisions of spiders — the first having four 

 spinnerets and four air-sacs, the second two air-sacs and six 

 spinnerets. The former are known as Mygalidce, or crab-spiders, 

 such as the large Tarantula, or Bird-spiders, of the tropics. One 

 large species is found in Britain — ^namely, Atypus Sulzeri. This 

 carnivorous araneid excavates a subterranean gallery in damp 

 places, in which the female, amongst the lining of white silk the 



