434 EXTERNAL ANATOMY OF INSECTS. 



at least, in the Orfhoptera, a coriaceous lamina that se- 

 parates them in some sort from the body of the mandi- 

 ble a . Many insects, however, have mandibles without 

 teeth ; some merely tapering to a sharp point, others ob- 

 tuse at the end, and others truncated b . Of those that 

 have teeth, some have them on the inside at the base, as 

 Manticora, an African tiger-beetle c ; others in the mid- 

 dle, as StaphyMnus olens, a rove-beetle, Lethrus cepha- 

 lotes, &c. d ; others at the end, as many weevils [Curcu- 

 lio L.) e ; others again on the back, as the Rutelidce, a tribe 

 of chafers f , and Lethrus, a beetle just named; others 

 once more on the lower side of the base, in the form 

 of a tooth or spine, as in Melitta spinigera, a species of 

 wild-bee, and some of its affinities ? ; and lastly, others 

 on the upper side of the base in the form of a long tor- 

 tuous horn, as in that singular wasp Synagris cornuta F. 

 before noticed as a sexual character h . In the stag- 

 beetle tribes (LucanuslL.) these teeth are often elongated 

 into short lateral branches, or a terminal fork ! . They 

 are sometimes truncated, sometimes obtuse, and some- 

 times acute. 



But with regard to their land, it will be best to adopt 

 the ideas of M. Marcel de Serres ; for though his re- 

 marks are confined to the Orfhoptera, they may be ap- 

 plied with advantage to the teeth that arm the mandibles 



a Marcel de Serres ubi supra. 7. 



b See Plate XIII. Fig. 7- Kirby Mon. Ap. Angl. i. t. xiii./. 13. 

 and t. xii. neut.f. 10. c p LATE XXVI. Fig. 19. 



d Oliv. Ins. no. 42. t. If. 1. and no. 2. t. If. 1. b. 

 e Plate XXV7. Fig. 1 6, 18. f Ibid. Fig. 21 . 



g Mon. Ap. Angl. i. t. iv. Melitta. f. 5—8. 

 h Drury Ins. ii. t. xlviii./. 3. See above, p. 315. 

 1 Oliv. no. 1. t. v.f 16. &c. t. in.f. 7. 



