SPIDER GOSSIP. 



03 



as a bridge by which to cross the gaps. Now, if this thread 

 were sticky, the insect could not do this, because, if it so much as 

 stepped on it, it would either get entangled in it, or break it. 

 What then is done ? The ring-thread which the spider has spun, 

 beginning at the centre and finishing at the circumference, is no 

 more sticky than the radii, and equally useless for catching flies. 

 It has, indeed, no such purpose, and is intended merely as a series 

 of temporary " bridges " for crossing the inter-radial spaces, to 

 enable the insect to fix its dangerous, sticky thread without risk of 

 entanglement. It should be noted that its rings are much fewer 

 and farther apart than the viscid rings. As soon as it is made, 

 the spider begins again, this time not at the centre, but at some 

 point in the circumference of the web, and lets out its sticky 

 thread from the lower spinnerets, using, as I have said, the non- 



rV5 cf 



Short lengths of web of Epeii^a diadema. a h, two ring-threads, with 

 their viscid globules ; c, one radius, non-adhesive. Magnified 

 375 diameters. 



adhesive ring-thread as bridges for crossing the gaps between the 

 radii. Each division is bitten off as soon as it has been thus 

 used, for it is no longer wanted, and the presence of extra 

 non-adhesive threads in the finished web would obviously impair 

 its efficiency as a fly-trap. The sticky thread is fastened down to 

 each radius by the hind feet, as fast as it streams from the spinners. 

 It does not appear to stick at first, and the viscid fluid which coats 

 it, and to which its adhesive power is due, does not run into drops 

 for some moments. It is much more elastic than the radii, and 

 two small pieces of it, with its drops, are drawn in Fig. 12. I do 

 not think that the fluid is itself sticky— only viscid like glycerine ; 

 but drops naturally stick. Once this thread is fastened down, the 



