AllACHNIDA. 



645 



in No. 2, from each of which there escapes as many little 

 drops of a liquid as there are holes, -which, .drying the 

 moment they come in contact with the air, immediately 

 form so many delicate threads. Immediately after the 

 filaments have passed through the pores, they unite first 

 together, and then with those of the next, to form one 

 common thread ; so that the thread of the spider is com- 



V 



Fig. 298. Epeira diadema, Diadem Spider. 



posed of a large number of minute filaments, perhaps 

 many thousands, of such extreme tenuity that the eye can- 

 not detect them until they are twisted together into the 

 working thread. In the two pairs of spinnarets a different 

 anatomical structure can be detected; the pair above, 

 which are a little the longest, show a multitude of small 

 perforations, the edges of which do not project, and which 

 therefore refcemble a sieve. The shorter pair have pro- 

 jecting tubes independent of the perforations which exist 



