436 EXTERNAL ANATOMY OF INSECTS. 



apex of those of the leaf-cutter bees may be regarded as 

 between the incisives and laniaries ; and the pointed man- 

 dibles without teeth may be deemed as terminating in a 

 laniary one a . The lower part of the inner or concave 

 surface of the mandibles of grasshoppers will supply you 

 with instances of the molary teeth, and the apex, also, of 

 those of some weevils, as Curculio Hancocki K. b But 

 the most remarkable example of a molary organ is exhi- 

 bited by many of the Lamellicorn beetles, especially those 

 that feed upon vegetables, whether flower or leaf. — 

 Knoch, who indeed was the first who proposed calling 

 mandibles according to their teeth, incisive, laniary, or 

 molary, but who does not explain his system clearly, 

 observed that the mandibles of some Melolonthae have a 

 projection with transverse, deep furrows, resembling a 

 file, for the purpose of bruising the leaves they feed upon c : 

 and M. Cuvier, long after, observed that the larvse of 

 the stag-beetle have towards their base a flat, striated, 

 molary surface ; though he does not appear to have no- 

 ticed it in any perfect insect d . This structure, with the 

 exception of the Scarabceidce and Cctoniadce, seems to 

 extend very generally through the above tribe; since it 

 may be traced even in Geotricpes, the common dung- 



a Plate VI. Fig. 12. and XIII. Fig. 5. b'". 



b Plate XXVI. Fig. 16. 



c I was not aware that Knoch had observed this part, till some 

 time after the publication of my paper On Mr. William MacLeay's 

 Doctrine of Affinity and Analogy (see Linn. Trans, xiv. 105 — ), when 

 I happened to meet with it in a letter from a friend, received more 

 than thirteen years ago; but without any reference to the work of 

 Knoch, in which it was stated. It was doubtless taken from his 

 Beitrage zur Insehtengeschichte. 



d Anat. Comp. hi. 321 — . 



