THE GENESIS OF SNAKES. 



339 



Utilizing 

 Web 

 Frag- 

 ments . 



this use of the trapline, or the similar use of the footlines, aids in entang- 

 Hng insects, I can very well believe that it may frequently contribute more 

 or less to this result. This may be done either by the mechanical momen- 

 tum of the lines which are swung around the insect by the sudden tighten- 

 ing and releasing thereof ; or by exciting the insect and causing it to move 

 its wings and legs, thus entangling it more and more within the viscid 

 spirals. 



A young Epeira domiciliorum well illustrated the general tendency in 

 this direction when under special compulsion of circumstances in the cap- 

 ture of prey. When observed, her web had been badly damaged 

 by insects. At the sides all the spiral lines had disajipeared, 

 and a few patched radii alone remained. On the upper part of 

 the orb were a few spirals. A segment remained in tolerable 

 condition on the lower part of the 

 snare, but it also was greatly damaged by the 

 fracture of some of the radii. The spider had 

 spun a number of lines from the hub to the spin- 

 ning space, and these, with the remaining radii, 

 were gathered together in all the fore feet and 

 pulled very taut. The upper part of the web was 

 also tightened, but to a less extent, by the action 

 of the two hind feet. But on the sides the web 

 appeared to hang loose, and, taking a side view of 

 it (Fig. 330), one could readily see how the whole 

 action of the spider was bent upon keeping the 

 valuable portion of the web in a taut condition, 

 ready for service, Mhile the other parts were left 

 to take care of themselves. This spider had lit- 

 tle more space available for the capture of prey 

 than a Triangle spider with a complete web. I 

 have no doubt that, had I w-aited to see an insect strike the sector thus 

 controlled by the fore feet, I should have seen this Orbweaver let go the 

 clustered traplines held iii her claws precisely as the Ray and Triangle 

 spiders habitually release their single traplines. 



Another example was afforded by the snare of a full grown Stellate 



spider (Epeira stellata), which by some rare ill fortune had lost the entire 



central part of the orb. Yet the animal was not discouraged, but 



+ fi^T held her place at the hub with her legs doubled up in the manner 



usual to the species, and holding quite taut her little remainder 



of a web out on the margin, together with the connecting radii that had 



survived the wear and tear. Here, again, a few sectors quite disconnected 



from the hub were doing duty for trapping insects, as is habitually the 



case with the Ray spider. (See Fig. 331.) (Compare Fig. 331 with Fig. 



187, page 196.) 



Fig. 330. Epeira domiciliorum, 

 trapping with a fractured snare. 



