OF NATURAL HISTORY. 97 



The fame effe£t is produced in a room jull: light enough to 

 render the animals vifible. Thefe trials, which I have oftea 

 repeated, feem to indicate that flies, if they are really depriv- 

 ed of ears, are endowed with an analogous fenfe, though we 

 are ignorant of its fituation. 



Naturalifts have limited the fenfes of infects to thofe of 

 feeing and feeling. But the above remarks render it more 

 than probable that flies poflefs likewife the fenfes of fmelling 

 and of hearing : Neither fhould the fenfe of tafte be denied 

 them j for, though they may be aflifted by fmelling to dil- 

 cover and feleft their food, we cannot fuppofe that Nature 

 has denied them the pleafure which other animals fo univer- 

 fally derive from eating. Befides, an agreeable fenfation, 

 fimilar to that of tafle, muft accompany an action which re- 

 moves the pain arlling from hunger. 



The mouth of infecSts is generally placed in the under 

 part of the head •, but, in fome, it is fituated in the breaft. 

 The jaws, inflead of being horizontal, are often tranfverfe, 

 and furnifhed with teeth. The greater number of winged 

 infects are provided with a probofcis or trunk, an inftrume!;it 

 by which they extra6l the juices from animal or vegetable 

 fubftances. The probofcis of infects is a machine of a very 

 complicated nature. In butterflies, the probofcis is. fituated 

 precikly between the two eyes. Though fome of them ex- 

 ceed three inches in length, they occupy but a fmall fpace. 

 When a butterfly is not in queft of food, the probofcis is 

 rolled up in a fpiral form, flmJlar to that of a watch-fpring, 

 each fuccefflve ring covering the one which precedes. The 

 fubfhance of the probofcis has fome rcfemblance to that gi 

 horn. It tapers from the bafe to the extremity. It is com- 

 pofed of two fimilar and equal parts, each of which is co#i- 

 cave, and, when joined, form three diflin^l tubes. Reaumur 

 has rendered it probable, that thefe tubes enable the animals 

 to extradl the juices of plants, to condufl air into thik 



