342 MOTIONS OF INSECTS. 



question; and thus the animals may be conveyed from 

 furrow to furrovv' or straw to strav/ less circuitously, 

 and with less labour, than if they had travelled over 

 the ground. As these creatures seem so thirsty, may 

 we not conjecture that the drops of dew, with which 

 they are always as it were strung-, are a secondary 

 object with them ? So prodigious are their numbers, 

 that sometimes every stalk of straw in the stubbles, and 

 every clod and stone in the fallows, swarms with them. 

 Dr. Strack assures us that twenty or thirty often sit 

 upon a single straw, and that he collected about 2000 

 in half an hour, and could have easily doubled the 

 number had he wished it : he remarks, that the cause 

 of their escaping the notice of other observers, is their 

 falling to the ground upon the least alarm. 



As to what becomes of this immense carpeting of 

 web there are different opinions. Mr. White conjec- 

 tures that these threads, when first shot, might be en- 

 tangled in the rising dew, and so drawn up, spiders and 

 all, by a brisk evaporation, into the region where the 

 clouds are formed^. But this seems almost as inad- 

 missible as that of Hooke, before related. An ingeni- 

 ous and observant friend, thinking the numbers of the 

 flying spiders not sufficient to produce the whole of the 

 phenomenon in question, is of opinion that an equi- 

 noctial gale, sweeping along the fallows and stubbles 

 coated with the gossamer, must bring many single 

 threads into contact, vvhich, adhering together, may 

 gradually collect into flakes ; and thit being at length 

 detached by the violence of the wind, they are carried 

 along with it : and as it is known that such winds often 



^ Nat. Hint. i. SW, 



