68 MANDIBULATA. — COLEOPTERA. 



Obs. — In the construction of the foregoing tahle *, I have endeavoured as far as 

 possible to select such characters^ chiefly external, as are constant in both 

 sexes ; it being manifestly impossible to detect the genera to which the females 

 of this family belong, by those which are laid down as primary divisions by 

 M. Latreille and De Jean ; though after their and Mr. Mac Leay's candid 

 admission of their inability, from our present knowledge, either to frame such 

 discriminative characters as wiU positively embrace, or separate, all the groups, 

 and exhibit their natural affinities throughout, I cannot presume to assert that 

 I have been more successful in my attempts : on the contrary, a transient in- 

 spection of the above table wUl readily show that the genera are not all placed 

 with reference to their actual affinities, although it may satisfactorily connect 

 one or two that have hitherto been separated : and as examples of the dif- 

 ficulties with which we are assailed, in our investigations of the affinities of 

 this extensive family, I shall direct the attention of the student to the genera 

 Omaseus, Steropus, and Harpalus, from the two former having been re- 

 cently ably illustrated by Mr. Curtis, with reference to their generic cha- 

 racters, and the latter from its extent, and the variation of form among the 

 species: and upon inspection of the trophi of Omaseus and Steropus, the 

 difference will be found not greater than usually occurs among the species of 

 any extensive genus, the chief distinctions being drawn from subsidiary cha- 

 racters, viz. the form of the thorax and elytra ; characters which are far too 

 unsatisfactory in this family, although the above genera are sufficiently 

 distinct in, what is technically called, habit ; the form of the thorax in the 

 first genus being very dissimilar in the different species, that of O. aterriraus 

 being rounded behind, while O. nigrita has acute basal angles : and if the 

 condition of being apterous enter into the generic character, O melanarius 

 must be formed into a new genus, as its habit and depressed body wiU not 

 allow of its being associated with Steropus. Again in Harpalus as above re- 

 stricted (of which genus I possess above fifty indigenous species), there is 

 the most conspicuous difference in the form of the thorax, as well as in the 

 convexity of the body, and termination of the elytra : in by far the greatest 

 number of the species the former has the base nearly straight, as broad or 

 broader than the body, to which it is closely appUed, with the hinder angles 

 in one division very acute, and in a second very obtuse ; others again have 

 the thorax rather narrower at the base than the body, the hinder angles 

 distinctly rounded, and the thorax itself somewhat remote from the body, as 

 in the Scaritidee : — this division of the genus is evidently rare in Britain, as I 

 have hitherto seen but the three species which are in my own cabinet. 

 Again, the bodies of H. serripes and its affinities are almost as convex as in 

 Zabrus, while H. thoracicus, Leach MS. (which is congenerous with H. crassus, 

 &c. Sturm), has the body as much depressed as in OiJdes, and the thorax 

 itself is much broader than the elytra, as in that insect. Other instances 

 might be cited ; but enough has been adduced for the present ; I shall there- 

 fore merely add, that in Harpalus, Ophonus, Stenolophus, Trechus, and 



* Vide Haustellata, vol. i. p. 5, note, in allusion to conterminous forms. 



