88 THEPHILOSOPHY 



Naturalifts have limited the fenfes of infeds 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 

 fliould the fenfe of tafte be denied them ; for, though they may be 

 aififted by fmelling to difcover and feled their food, we cannot fup- 

 pofe that Nature has denied them the pleafure which other animals 

 fo univerfally derive from eating. Befides, an agreeable fenfation, 

 fimilar to that of tafte, muft accompany an adion which removes 

 the pain arifmg from hunger. 



The mouth of infe£ts is generally placed in the under part of the 

 head ; but, in fome, it is fituated in the breaft. The jaws, inftead 

 of being horizontal, are often tranfverfe, and furnifhed with teeth. 

 The greater number of winged infedts are provided with a probofcis 

 or trunk, an inftrument by which they extrad the juices from ani- 

 mal or vegetable fubftances. The probofcis of infedls is a machine 

 of a very complicated nature. In butterflies, the probofcis is fitu- 

 ated precifely between the two eyes. Though fome of them exceed 

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

 a butterfly is not in queft of food, the probofcis is rolled up in a 

 fpiral form, fimilar to that of a watch-fpring, each fuccefTive ring 

 covering the one which precedes. The fubftance of the probofcis 

 has fome refemblance to that of horn. It tapers from the bafe to 

 the extremity. It is compofed of two fimilar and equal parts, each 

 of which is concave, and, when joined, form three diftind tubes. 

 Reaumur has rendered it probable, that thefe tubes enable the ani- 

 mals to extrad the juices of plants, to condud air into their bodies, 

 and to convey the fenfation of fmelling. Hence the probofcis of in- 

 feds is an inftrument which ferves them for a mouth, a nofe, and a 

 wind-pipe. 



r The 



