Memoirs on the coleoptera

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near the base, the costse not cariniform but evidently an extreme
development of the obtuse ridges of the preceding group and sometimes
taking that form in the present group; body rather small,
sometimes extremely slender in the male, always deep black throughout
Group III
5 Pronotum coarsely and densely punctate, sometimes medially impressed
at base as in Group I, deplanate or concave and reflexed
at the sides; elytra with vestiges of three fine costules on each, the
outer of which joins the margin near the base; side margin obsolescent,
sometimes rather acute and distinct but not cariniform and
reflexed, except near the humeri; body very convex Group IV
6 Elytra widest at or before the middle, more gradually acuminate
behind than in any other group, the prothorax rounded or angulate
at the sides; body always deep black throughout, very convex;
general form of the body strikingly imitative of Eleodes.. . .Group V
Elytra widest well behind the middle, obovoidal, variably convex and
diversified in coloration, -7
7 Sides of the very convex prothorax not explanate or reflexed but
having a fine cariniform margin; eyes larger than in any other group
and less transverse than elsewhere in the tribe so far as observed.
Group VI
Sides of the prothorax, which is always much less convex, concave and
reflexed, though more or less narrowly; body generally more or less
piceo-rufous, sometimes deep black Group VII
These groups are not quite so strongly differentiated as those of
Pelecyphoms, but, at the same time, are to be considered subgeneric
in nature, as the fades is quite distinctive in each and a species can
be placed in its proper group without a moment's hesitation.
Group I Type marginal us Lee.
The species of this group are the largest of the genus and are
confined to the arid regions of Arizona and western New Mexico,
particularly to the southward, where they are numerous and
greatly diversified in form and sculpture.
Elytra with small, sometimes very minute, sparse punctures, the pronotal
punctures generally very minute and sparse
2
Elytra with coarse, much closer-set punctures, the pronotal punctures
rather coarse and dense as a rule 1 1
2 Marginal carina of the elytra short, never extending materially
behind the middle
Marginal carina long, extending at least to the convex apical declivity.. 6
3 Pronotum laterally rather abruptly deplanate but not at all reflexed
and coarsely, closely, transversely rugose .4
Pronotum similarly coarsely and closely rugose at the sides but sensibly
reflexed
4 Body blackish, alutaceous, the elytra dark rufo-piceous; head deeply,