WEAVERS OF ROUND WEBS. 



113 



Head 



Down- 



•ward 



Natural 



toward the web. The posture at the hub, therefore, is the natural one 

 taken when, upon disturbance of the snare, the aranead runs down the 

 trapHne to the centre. Convenience and habit combine to fix the posture 

 as we find it. 



Moreover, the majority of vertical orbwebs have the longer part of 

 the spiral surface available for capture of insects below the median 



horizontal line, a fact caused, as has been seen (Chapter V.) bj' 



the corner loops that stretch downward beyond the concentrics. 



Thus the habitual posture of the spider really gives the widest 



command of the snare, 



being the best posture 

 from which to sally forth against 

 entangled insects. 



Still further it may be said, 

 that the nest does not necessarily 

 afford the readiest or even safest 

 retreat in case of assault by ene- 

 mies. It is much easier for the 

 spider to fling herself from the 

 web and drop to the ground than 

 to mount to her nest. Not only 

 is this movement executed with 

 marvelous dispatch, but, as I can 

 well testify from my experience 

 in collecting specimens, the con- 

 cealment afforded by the grass, 

 leaves, etc., at the surface is very 

 complete, especially as the ani- 

 mal instantly curls herself into 



a ball and lies in the foliage Fig. 102. Position of Epelra upon her hub, to show command 



with the rigidity and stillness 



of death. On the whole the inverted posture of the Orbweaver, however 

 unnatural it may seem to us, is precisely the one which nature has made 

 most advantageous to the sjiider. 



The legs of the Orbweaver are rarely, never habitually, 1 think I may 

 say, spread out equally over the hub. The two fore feet on each side 



are approximated, and spread out from the body at an angle 

 Feet Com- j-(-jQj,g ^j. jggg acute. (See Fig. 102.) The two hind pairs of legs 

 g are similarly placed, although the short third pair is more 



likely to be extended directly from the body. The approxima- 

 tion is sometimes so close that the legs are arranged X-shape. If the 

 claws be closely examined as the spider thus hangs, they will be seen 

 very generally to clasp the lines of the hub at or near the points where 

 several radii unite, or to hold on by little pyramidal clusters of threads 



