92 



RANDOM NOTES ON NATURAL HISTORY. 



shows almost human intelligence. A base 

 line as a stay or support of the web is at- 

 tached vertically to the trunk of a tree ad- 

 hering only at the two ends. From this 

 four lines, always this number and no more, 

 start at equal distances from each other 

 and converge to an apex, or acute angle, 

 and then extend as a single line to some 

 fixed point. These four lines correspond to 

 the radii in the ordinary web, and the trans- 

 verse elastic lines correspond to the con- 

 centric circles of the same. The web when 

 finished is considerably longer than the dis- 

 tance between the two points of attachment , 

 and this slack line is for a purpose which 

 is the most striking evidence of the intelli- 

 gence of this spider. The spider takes up 

 the slack herself; and wonderful as is the 

 piece of work which she has accomplished, 

 her management of this web in taking her 

 prey is still more wonderful. Although in 

 spinning the ten transverse lines she is 

 believed to make 9,000 movements with 

 her hinder feet, 3'et, without a moment's 

 rest, she takes her place when the web is 

 finished, on the single line between the 

 apex and the point of attachment behind 

 her. Hauling the single line taut behind 

 her with her hinder feet, she draws in the 

 web and makes it taut with her first and 

 second pairs of feet, precisely as a man 

 would haul a sagging hammock by pulling 

 at the single line at the end. The third 

 pair of feet when desired may lightly hold 

 the slack rope. 



She is now read}'^ for business. For 

 hours, if necessary, she holds her place, 

 pulling taut the line and keeping the web 

 firm in position. AVhen the unlucky insect 

 comes in contact with her web, she sud- 

 denly lets go with her fore feet all the slack 

 line, and the web being lower and heavier, 

 the apex line is drawn taut, the net falls 

 outward and downward upon itself in a 

 kind of collapse, the transverse elastic 

 and gumm}' lines are brought nearer to- 

 gether, and thus the entanglement of the 

 prej'^ is insured. The spider then creeps 

 cautiously out on one of the radii, and if 

 she is not sure of her game runs back, 

 draws everything taut as before, and if the 

 insect is still in the toils again lets go with 

 a snap ; she has been known to repeat this 

 six times in succession before venturing a 

 personal encounter with her victim. 



But furthermore, and still more wonder- 

 ful, she has another method of using her 

 web. Contrary to the popular belief that 

 animals have but one way of doing things, 

 they often have several, conforming their 

 action to circumstances. For sometimes 

 this spider, instead of simply letting go the 

 slack line, takes more desperate measures. 

 Fastening a new line to the tree behind her 

 for her support, and reeling from her body 

 as she advances, keeping thus a line of pos- 

 sible retreat in the rear, she cuts the apex 

 line with her jaws, still holding to the line 

 in front of the cut she has made, and sup- 

 ported in the rear by the new line attached 

 behind ; she then again advances and 

 grasps all the radii where they meet and 

 cuts them with her jaws ; advances again, 

 rapidly, and bites off more still, holding by 

 what remains with her fore feet ; at each 

 successive cut, as she advances, the web 

 slackens, recoils and falls into collapse, 

 just as it did in the former case when she 

 simply let go the slack line, until, finally, 

 spreading her feet far apart she gathers up 

 the radii once more and with a quick move- 

 ment throws the whole of the web like a 

 blanket over her prey. Then grasping the 

 whole mass she transfers it to the third pair 

 of feet which roll it over and over, while 

 she holds on to the ruin of the web alone 

 with her fore feet, and with the hinder feet 

 she draws out from her spinners broad 

 bands of new silk, winding it around and 

 around the struggling insect, now hardly 

 visible. Having reduced insect, web, and 

 all, to a rounded mass, she seizes the whole 

 mass, the insect in his silken shroud, more 

 dead than alive, and mounts with it to the 

 recent scene of her waiting patience and 

 there devours her prey. This spider thus 

 completely sacrifices its web, the product 

 of so mucii toil and skill, and the capture of 

 a single insect involves the ruin of the cun- 

 ning machine elaborately built to accom- 

 plish it. 



As to webs in general, it may be said 

 that as the radii are generally covered with 

 the viscid gum, the web is very elastic, 

 yielding to the struggles of insects without 

 breaking, and withstanding the force of the 

 wind. If the wind is strong, however, the 

 spider shows her intelligence by loading the 

 web with sticks and small pebbles to hold 

 it firmly in place. 



