Kew : Snares or Snap-nets of Triangle Spiders. 



207 



and repetition of the vibration indicate that an insect is really entangled, 

 the spider awakes from her apparent apathy ; she lets g'o with her hind 

 feet ; the net, released from its tension, flies forward, and at the same time 

 flaps from side to side. The comparative inertia of the fly causes the two 

 or three cross-lines next to it on the side toward the apex to be, as it were, 

 propelled against it, and the entanglement is aided by the sidewise flapping 

 already mentioned ; as may be imagined, all this is pretty apt to involve 

 the fly beyond the possibility of escape ; but, if the spider does not feel 

 certain of this, she creeps backward again, foot over foot, as before, and 

 again springs her net ; and this I have seen repeated in quick succession 



six times before the spider has 

 ventured to make a personal 

 approach. She has already been 

 carried a little way towards her 

 prey by the snapping- of the net, 

 for she always retains her hold 

 of the apex-line by her first two 

 pairs of feet, and the third pair 

 serves to steady her as the 

 slack-line slips between them. 

 Advancing now to the junction, 

 she seems to ascertain the exact 

 location of the fly by pulling upon 

 the radii.* 



The snare as it appears when relaxed is shown in Fig-. 6 ; 

 comparing this with Fig-. 5 we see that the base-line is now 

 more nearly straight; and, the loop of slack having disappeared, 

 the trap-line is taut. 



Fig. 6. — The snare of Hy^tiotes cavatttst 

 relaxed for the entanglement of prey. After 

 Wilder, Popular Science Monthly, VI. (1875), 

 P- 651, Fi g- 9- 



* Wilder, 1875, I.e. In the paper of 1 S73, the snapping process is thus 

 described : by the loosing of the fourth feet, 'the strain is relaxed and the 

 whole net regains its original condition with a sharp snap, which causes 

 the elastic lines to vibrate in all directions and generally entangles two or 

 more of them upon the insect ; should this first attempt fail, the spider, 

 which has been carried sharply forward with the line . . again walks 

 backward ami again lets go; this is sometimes repeated six times in e,uiek 

 succession. ' 

 1900 July 2. 



