STUDY XI. 279 



It is of importance for us to be acquainted with, 

 at lead, fuch infects as deftroy thofe which are of- 

 fenfive to Man. We might turn their mutual hofti- 

 lity to good account, by converting it into the means 

 of our own repofe. The fpider catches the flies in 

 nets 1 the formicaléo furprizes the ants in a tunnel 

 of land; the four-winged ichneumon feizes the 

 butterflies on the wing. There is another ichneu- 

 mon, fo fmall and fo cunning, that it lays an egg 

 in the anus of the vine-fretter. Man has it in his 

 power to multiply at pleafure the families of in- 

 fects which are ufeful to him; and may find means 

 of diminifhing fuch as make depredations on his 

 agricultural pofleffions. The fmall birds of our 

 groves tender him, to the fame effect, fervices of 

 Hill greater extent, and accompanied with other 

 circumftances inexpreffibly agreeable. They are 

 all directed by inftinct to live in his vicinity, and 

 about the pafturesand habitations of his flocks and 

 herds. A fingle fpecies of them might frequently 

 be fufficient to protect the cattle from the infects 

 which infeft them through the Summer. 



There is in the North a gadfly, cailed Kourbma 

 by the Laplanders, and by the Learned, œjlrus 

 rangiferinuSj which torments the domeftic rein- 

 deer to fuch a degree as to force them in agony to 

 the mountains, and fometimes actually plague 

 them to death, by depofuing their eggs in the fkin. 



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