EXTERNAL ANATOMY OF INSECTS. 475 



and different food produce, — have remained essentially 

 the same, or they would not have answered the end for 

 which they were made, from that time to this. 



Having given you this particular account of the trophi 

 or organs of the mouth of insects, I must now make some 

 observations upon the other parts of the head. I have 

 divided it, as you see in the Table, xntoface and subface; 

 the former including its upper and the latter its lower 

 surface. Strictly speaking, some parts of the face, as the 

 temples and cheeks, are common to both surfaces ; but 

 I do not therefore reckon them as belonging to the sub- 

 face, which, exclusive of the mouth and its organs, con- 

 sists only of the throat, and where there is a neck, the 

 gida. 



i. Nasus a . — I shall consider the parts of the face in the 

 order in which they stand in the Table, beginning with 

 the nasus or nose. Fabricius has denominated this part 

 the clypeus, in which he has been followed by most mo- 

 dern Entomologists. You may therefore think, perhaps, 

 that I have here unnecessarily altered a term so gene- 

 rally adopted, and expect that I assign some sufficient 

 reasons for such a change. I have before hinted that 

 there is good ground for thinking that the sense of smell 

 in insects resides somewhere in the vicinity of this part; 

 and when I come to treat of their senses, I shall produce 

 at large those arguments that have induced me to adopt 

 this opinion : and if I can make out this satisfactorily, 

 you will readily allow the propriety of the denomination. 

 I shall here only state those secondary reasons for the 



a Plates VI. VII. XXVII. a. 



