. Bulletin of the British Museum (Natural History) Entomology. RECLASSIFICATION OF M£L/lA^Orf/5 GROUP 47. Figs 23-26 Mesocoxa and mesocoxal cavity and part of mesosternal groove ot (23) Melanotus vitlosus, C2-mesocoxa, EM2-mesepinieron, ES2-mesepistemuni, S2, S3- mesostemum & metastemum, (24) Anchiszombatya porrectifrons, (25) Priopus peregrinus, (26) P. homostictus. Straight or emarginate and parallel or divergent posteriad; the posterior margin is usually arcuate although in some species it is straight and in a few it is emarginate or notched. The dorsal surface may lie in the same plane
. Bulletin of the British Museum (Natural History) Entomology. RECLASSIFICATION OF M£L/lA^Orf/5 GROUP 47. Figs 23-26 Mesocoxa and mesocoxal cavity and part of mesosternal groove ot (23) Melanotus vitlosus, C2-mesocoxa, EM2-mesepinieron, ES2-mesepistemuni, S2, S3- mesostemum & metastemum, (24) Anchiszombatya porrectifrons, (25) Priopus peregrinus, (26) P. homostictus. Straight or emarginate and parallel or divergent posteriad; the posterior margin is usually arcuate although in some species it is straight and in a few it is emarginate or notched. The dorsal surface may lie in the same plane as the elytra or be more strongly inclined; it may be flat or slightly convex, strongly or feebly grooved or impressed longitud- inally. Preliminary studies have shown that the states of these characters merge into one another to such a degree and appear in so many combina- tions with each other that, as at present defined, they are of little use as key characters. Neverthe- less I believe that the appearance of the scutellum may well prove to be of some value as a diagnostic character at specific rank. The profile of the margin of the mesosternal groove (Figs 14, 23-26) has occasionally been mentioned in descriptions and examination of the available material has shown that it may be almost horizontal, slope anteriad, or be either distinctly or feebly angled and that, though the states merge into one another, there is little or no intraspecific variation. Unfortunately I have so far been unable to define the character states satisfactorily (but see #15, p. 94). I beheve that the outHne of the aperture of the mesosternal groove, which varies in shape from 'U' to 'V but which is rarely mentioned in descriptions, may also be of some value in distinguishing one species from another. Up to the present my investigations have failed to show any constant relationship between the shape of the mucro (p. 46) and the mesosternal groove. The mesostemum and metastemum abut be- tween the mi
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