FLIES. 273 



yet they readily moved their quarters when dis- 

 turbed ; a proof that, notwithstanding the conti- 

 nued frost, they were not actually torpid. 



FLIES. 



BESIDES the true horse-flies,* which settle on horses 

 in order to suck their blood, and which for this pur- 

 pose have their mouths furnished with a most for- 

 midable set of knives and lancets, there are hosts 

 of others, which hover about them in swarms in hot 

 weather, but which, having only a soft proboscis, 

 without any instruments for cutting or piercing the 

 hide, appear quite incapable of inflicting any sen- 

 sible injury. These consist of various species of 

 Musca and Anihomyia (Meig.), and perhaps other 

 genera ; and their sole object, as it appears to me, 

 is to suck the perspiration of the animal when 

 heated. They tease by their numbers, and by the 

 constant titillation they keep up in settling; some 

 horses, however, get habituated to them, and almost 

 disregard them entirely. 



If the leaves of different trees, but especially the 

 lime and ivy, be examined in an autumn morning 

 after a cold night, they will be found in many 

 places covered with flies, having all the appearance 

 of life, but which upon being touched are found to 



^ Different species of Tabanus, Hcematopota, and Chrysops, 

 Meig. 



N 5 



