650 THE POPULAR SCIENCE MONTHLY. 



as in Nature. The remaining interradials are formed in like manner, 

 their number varying from six to fifteen. 



It will be seen that, by first making the double line nearest the 

 base-line, and afterward the others in their order, the spider avails 

 herself of the fact that a less and less distance is to be successively 

 gone over before crossing from one radius to the next ; whereas, if 

 she made the shortest double line first, then she would either be liable 

 to entangle the other if she crossed at the, apex, or, if she went around 

 by the base-line, the distances to be gone over would constantly de- 

 crease inversely to the lengths of the double lines themselves, causing 

 either waste or entanglement. 



It is not yet certain just how long a time is required for making 

 the entire net ; but, in one case, the spinning of the five lesser viscid 

 lines occupied the spider ten minutes ; the other and longer ones may 

 have taken twice as long ; and, as the return-movements are rapidly 

 executed, we may say that, for at least half an hour, the little spider is 

 moving her hinder legs together and with great precision at the rate of 

 300 times per minute, making the total number of movements 9,000 ! 



How is the Net used ? If the making of the net is peculiar, its 

 use is even more remarkable ; and here, fortunately, few points re- 

 main to be cleared up ; for the spider's response to a disturbance of 

 her net by a fly is so prompt that one may, at any time, witness the 

 operation. 



At the close of what to the observer seems a pretty energetic 

 exercise of all her faculties and powers, the spider, without a mo- 

 ment's rest, goes to a point upon the apex-line about an inch from the 

 origin ( O), and, firmly grasping the line between the first and second 

 pairs of feet, she walks backward, foot over foot, until her hinder feet 

 are caught in the attachment itself, or in the thickened line near it ; 

 in so doing, a certain amount of slack-line has been furled up between 

 the two points held by her hinder legs and the front ones ; this slack 

 is kept away from her body by means of the third pair, which are 

 shorter than the others. Evidently the effect of the above operation 

 is to draw the net toward the apex, the two middle radii being most 

 affected, and with them the central portion of the base-line to which 

 they are attached ; and the whole net assumes the appearance shown 

 in Fig. 1. 



It is now upon the stretch ; and the degree of tension is very con- 

 siderable, judging from the violence of the snap when it is let go ; 

 the exact amotint has not yet been measured, but, when it is borne in 

 mind that the spider remains motionless for hours, perhaps for days, 

 constantly holding her net ready for action, we may conclude that, as 

 is the case with other insects, her powers and her endurance are, in 

 proportion to her size, quite beyond what we are familiar with among 

 the higher animals. But our spider's ability to keep still is fully 



