MOTIONS OF INSECTS. 501 



abdomen pointing upwards, as if to shoot their thread previously to flying 

 off; wlien, upon my approaching to take a nearer view, they have lowered 

 it again, and persisted in disappointing my wish to see them mount aloft. 

 The rapidity with which the spider vanishes from the sight upon this occa- 

 sion, and darts into the air, is a problem of no easy solution. Can the 

 length of web that they dart forth counterpoise the weight of their bodies ; 

 or have they any organ analogous to the natatory vesicles of fishes^, which 

 contributes at their will to render them buoyant in the air? Or do they 

 rapidly ascend their threads in their usual way, and gather them up, till 

 having collected them into a mass of sufficient magnitude, they give them- 

 selves to the air, and are carried here and there in these chariots ? I must 

 here give you Mr. White's very curious account of a shower of these webs 

 that he witnessed. On the 21st of September, 1741, intent upon field 

 diversions, he rose before daybreak ; but on going out he found the whole 

 face of the country covered with a thick coat of cobweb, drenched with 

 dew, as if two or three setting-nets had been drawn one over the other. 

 When his dogs attempted to hunt, their eyes were so blinded and hood- 

 winked that they were obliged to lie down and scrape themselves. This 

 appearance was followed by a most lovely day. About nine a. m. a shower 

 of these webs (formed not of single floating threads, but of perfect flakes, 

 some near an inch broad, and five or six long) was observed falling from 

 very elevated regions, which continued without interruption during the 

 whole of the day ; and they fell with a velocity which showed that they 

 were considerably heavier than the atmosphere. When the most elevated 

 station in the country where this was observed was ascended, the webs 

 were still to be seen descending from above, and twinkling like stars in the 

 sun, so as to draw the attention of the most incurious. The flakes of the 

 web on this occasion hung so thick upon tbe hedges and trees, that baskets 

 full might have been collected. No one doubts, he observes, but that 

 these webs are the production of small spiders, which swarm in the fields 

 in fine weather in autumn, and have a power of shooting out webs from 

 their tails, so as to render themselves buoyant and lighter than the air.^ 

 In Germany these flights of gossamer appear so constantly in autumn, 

 that they are there metaphorically called " Der jiiegender Sommer" (the 

 flying or departing summer) ; and authors speak of the web as often hang- 

 ing in flakes like wool on every hedge and bush throughout extensive 

 districts. 



Here we may inquire — Why is the ground in these serene days covered 

 so thickly by these webs, and what becomes of them ? What occasions 

 the spiders to mount into the air, and do the same species form both the 

 terrestrial and aerial gossamer? And what causes the webs at last to fall 

 to the earth ? I fear I cannot to all these queries return a fully satisfac- 

 tory answer; but I will do the best I can. At first one would conclude, 

 from analogy, that the object of the gossamer which early in the morning 

 is spread over stubbles and fallows — and sometimes so thickly as to make 

 them appear as if covered with a carpet, or rather overflown by a sea of 

 gauze, presenting, when studded with dew-drops, as I have often witnessed, 

 a most enchanting spectacle — is to entrap the flies and other insects as 

 they rise into the air from their nocturnal station of repose to take their 



1 Cuvier, Anat. Comp. i. 504. « Nat. Hist. i. 325. 



