348 ARACHNIDA ARANEAE CHAP. 



of their vast numbers and regularity, the circumstance naturally 

 excited great wonder and admiration. Black wall l estimated that, 

 in a fourteen-inch net of Epeira cornuta, there were at least 

 120,000 viscid globules, and yet he found that its construction 

 occupied only about forty minutes ! The feat, from his point of 

 view, must be allowed to be rather startling. 



As a matter of fact, the thread, on being slowly drawn out, 

 is uniformly coated with viscid matter which afterwards arranges 

 itself into beads, the change being assisted by the sudden libera- 

 tion of the stretched line. 



Boys' 2 has 'Shown their formation to be quite mechanical, and 

 has obtained an exact imitation of them by smearing with oil a 

 fine thread ingeniously drawn out from molten quartz. The oil 

 arranged itself into globules exactly resembling the viscid 

 " beads " on the spider's line. If the web be carried bodily away 

 on a sheet of glass, as above described, while the spider is engaged 

 upon the spiral line, the experimenter will have permanent 

 evidence of the manner in which the globules are formed. The 

 last part of the line will be quite free from them, but uniformly 

 viscid. Tracing it backwards, how r ever, the beads are soon found, 

 at first irregularly, but soon witli their usual uniformity. The 

 thread which the spider has thus " limed " for the capture of 

 prey is really two-stranded the strands not being twisted, but 

 lying side by side, and glued together by their viscid envelope. 



The snare is now practically complete, and the proprietor 

 takes up her position either in the centre thereof, or in some 

 retreat close at hand, and connected with the hub by special 

 lines diverging somewhat from the plane of the web. Not- 

 withstanding the possession of eight eyes which, in sedentary 

 spiders, are by no means sharp-sighted it is mainly by the sense 

 of touch that the spider presently becomes aware that an insect is 

 struggling in the net. She immediately rushes to the spot, and 

 suits her action to the emergency. 



It' the intruder is small, it is at once seized, enveloped in 

 a Kami of silken threads drawn out from the spinnerets, and 

 rai'Hed off to the retreat, to be feasted on at leisure. If it seems 

 formidable it is approached carefully especially if armed with a 

 sting and silk is deftly thrown over it from a safe distance till 

 it is thoroughly entangled, and can be seized in safety by the 



1 llei>. JJrit. Ass. 1844, p. 77. - Xulnrc, xl., 1889, p. 250. 



