EXTERNAL ANATOMY OE INSECTS. 42J 



the ligula of Fabricius as the labium, and called the la- 

 bium of that author the mentum*', but afterwards he gave 

 the name of labium to the whole middle piece of the 

 lower apparatus of the mouth — calling the upper piece, 

 with Fabricius, the ligula, and retaining the denomina- 

 tion of mentum for the lower b . 



If the circumstances of the case are duly considered, 

 I think you will be convinced that the term under-lip, 

 or labium, should be confined to that part which the 

 learned Dane so named. For I would ask, Which is 

 the part on the under side of the head that is the anta- 

 gonist, if I may so speak, of the upper-lip or labrum ? 

 Is it not that organ which, when the mouth is closed, 

 meets that part, and in conjunction with it shuts all in ? 

 Now in numerous insects, particularly the Lamellicorn 

 beetles {Scarabceus and Lucanus L.), this is precisely the 

 case. In the Predaceous beetles, indeed, (Cicindela, Ca~ 

 rabus, Dytiscus L. &c. ) the under-lip does not meet the 

 upper, to close the mouth and shut in the tongue ; nei- 

 ther can the tongue be said so to do, but only, from some 

 circumstances connected with its manner of taking its 

 food, it is requisite that the last-mentioned organ should 

 not be retractile or covered ; but its miscalled mentum 

 is still the analogue of that part which helps to close the 

 mouth in the former tribe. Should not this, therefore, 

 which so often performs the office, be distinguished by the 

 name, of a lip ? Again, is it not rather incongruous to 

 consider that organ which confessedly more or less per- 

 forms the office of a tongue, as a part of the lip ? Though 

 it often wears that appearance, yet I believe, if the mat- 



- Gen. Crustac. el Ins. i. 180. b N. Diet. d'Hist. Nat. iv. 246. 



