BRACHELYTRA. 83 



somewhat conical tooth, rather obtuse with a lateral prominence; then folloAV three 

 flat rather distant teeth emarginate at the apex, which appear to act as incisives, 

 intermixing somewhat of a molary structure; and next succeeds the molary plate: 

 now this is as dissimilar as possible to the toothless mandible of a Dytiscus. 6 The 

 maxillae are equally dissimilar, 7 those of Hydrophilus approaching those of a Silpha, 

 except that the spine on the lower lobe is truncated, and terminates in two ungui- 

 form bristles. The lower-lip and the tongue also exhibit no resemblance. 8 



The affinity, therefore, of Dytiscus and Hydrophilus, cannot be proved by those 

 characters, which are usually and properly regarded as the most essential indica- 

 tions of it; and recourse must be had to characters that have been judged less 

 important, such as their being cohabitants of the same element, exhibiting a strik- 

 ing resemblance in their general aspect and form, and in their external parts and 

 organs : and here I must candidly own, that, with the exception of the antennas, 

 and the hands of the male, the resemblance is most striking, and can scarcely be 

 the effect of any thing, for analogy seldom extends to so many points of agreement, 

 but a near approach to each other. 



It may be farther argued, that some insects of the tribe make a nearer approach 

 in their more essential characters than Hydrophilus itself — this appears to be the 

 case with Spercheus, with respect to the palpiform or upper lobe of its maxillae, 9 

 Parnus in its mandibles, 1 &c. and future observers may make further discoveries. 



The above observations, however, prove that M. Latreille was not led by mere 

 system to doubt the connection of the two groups in question. His greatest error, 

 as it seems to me, was that of placing his Serricornes (Buprestis, Elater, &c.) be- 

 fore his Clavicornes and Palpicornes, which clearly have no business there, since 

 they separate tribes that ought not to be disunited. To me the last-named tribe, 

 or Philhydridce of Mr. Mac Leay, appears to bear the same relation to the Hydra- 

 dephaga, that the former, or Necrophaga of the same author, do to the Geadephaga , 

 but there seems to be an osculant group necessary to connect the latter, which ap- 

 pears not wanted in the former. The group to which I allude is the Brachelytra , 

 or Staphylinus of Linne : and these M. Latreille, though they connect at least in 

 two points with the Geadephaga, and scarcely in any with the Hydradephaga, has 

 placed after the latter : nor could he do otherwise in a linear arrangement, without 

 breaking up the great and natural group of the Adephaga ; unless indeed he had 



6 Compare Curtis Brit. Ins. v, t. 239, / 2, with iii, t. 99, / 2. 7 Ibid. /. 2. s Ibid. /. 4. 



9 N. D. D'H. N. xxxi, 573. Annulos. Javan. i, 33. 

 1 Oliv. Ins. iii, 41, £. i, /. l,b; comp. Curtis Brit. Ins ubi supr. /. 2. 



M 2 



