264 AMERICAN' SPIDERS AND THEIR SPINNINGWORK. 



, r 



force exerted from above. Fifth, suddenly and simultaneously the eight 

 claws are unloosed, and the spider mounts with a sharp bound, apparently, 

 and (sixth) floats off with the back downward, usually, but sometimes with 

 this position reversed. Seventh, at first the abdomen seems to be in ad- 

 vance, -but generally the body is turned so that the head rides in front. 

 Eighth, the ray of threads is apparently grasped with the feet and floats 

 out in front, upon which (ninth) sometimes the spider will climb upward, 

 as though to adjust the centre of gravity. Meanwhile (tenth) a thread or 

 cluster of threads issue from the spinnerets and float out behind, leaving 

 the spider to ride in the angle of the two diverging rays, or, as it some- 

 times happens, of three, which are widely separated at the upper free 

 ends. Eleventh, the feet seem to be united by delicate filaments, which 

 would serve to increase the buoyancy of the balloon. Twelfth, the spider 

 is now carried forward by the wind, riding for long distances in an open 

 space, and often borne high upward upon ascending currents. Thirteenth, 

 the anchorage of this miniature balloon appears at times to be within the 

 spider's own volition, by the fact that it can draw in with its claws the 

 forward ray and gather it in a white roll within the mandibles. But 

 most frequently the balloonist is stopped by striking against some ele- 

 vated object, or by the subsidence of the breeze. A bright warm day in 

 October is commonly chosen for the ascent, and judging from the pres- 

 ence of a number of dry moults, apparently of the same species of spider 

 observed in flight, the animals had recently cast their skins. 



IV. 



The greatest height to which I have seen spiders ascend is about one 

 hundred and fifty feet ; but, undoubtedly, they often rise much higher. 

 Dr. Lincecum observed the gossamer balloons of certain Texas 

 species floating at an altitude of one to two thousand feet. 1 

 . e Blackwall found ascending currents of air acting with such 

 force upon the gossamer streamers as to raise them in the atmos- 

 phere to a perpendicular height of at least several hundred feet. 2 Dr. 

 Martin Lister, the earliest observer of the habit (A. D. 1670), says: "As 

 to the height they are able to mount, it is much beyond that of trees or 

 even the highest steeples in England. This last October the sky here 

 upon a day was very calm and serene, and I took notice that the air was 

 very full of webs. I forthwith mounted to the top of the highest steeple 3 

 in the Minster |York], and could thence discern them yet exceeding high 

 above me ; some that fell and were entangled upon pinnacles, I took and 



1 " The Gossamer Spider," American Naturalist, 1874, page 592. 



2 Trans. Linn. Society, Vol. XV., page 453. 



3 The central and two western towers are 201 feet high. Cathedrals and Al>l>cys of 

 <iii-.it Britain, I>r. Wheatley. 



