Memoirs on the coleoptera

CERAMBYCID.E 345
uniting longitudinally by an angular extension of the anterior
of the two and not the posterior, the longitudinal distance between
the blotches, as in conjnncta, very much shorter than the
length of the blotches and a little less than the distance separating
the large transverse blotches in bifasciata, though even there it is
less than the length of the blotches and very different from the
condition in medialis; antennae very slender, one-half longer than
the body, nearly as in the preceding but with still shorter three
penultimate joints; abdomen finely but notably less closely punctate,
the fifth segment nearly similar but much less broadly
rounded. Length (cT) 8.5 mm.; width 2.0 mm. New Mexico
(Jemez Springs) parva n. subsp.
It will be noted that seven of the above described forms, counting
the eight assumed representatives of mactdata, are from a single
locality in New Mexico, which, in conjunction with the supposed
unusual variability of the species, might be held to render somewhat
injudicious or premature the definition of specific forms on the
lines above suggested; but in regard to this it can be said at least,
that structural and sexual characters have figured prominently or
even primarily in coming to this conclusion. There are many
marked structural differences throughout the series; for example,
the prothorax in robusta is parallel and nearly straight at the sides,
rapidly rounding at apex and base, giving that species a very dif-
ferent facies from the others, irrespective of size and ornamentation.
Argus and sexualis are also well marked species in the form and
proportion of the parts and in the male sexual characters. I am
almost certain that medialis is different specifically from any one of
the last three forms of the tables but place bifasciata as a subspecies
for the present. The two primary divisions of the genus indicated
above are founded upon structural differences of unequivocal weight,
this being strikingly evident on mere casual observation. Mr. Bates
describes certain prosternal peculiarities of coloration in differentiat-
relate ob-
ing the Mexican puncticollis and angustlcollis , which
viously to the males alone, but does not state that the coloration
noted is purely sexual; in the female the entire prosternal surface
is always red and much less strongly sculptured than in the male,
so far as noted. Both these species differ from any of our own in
having the prothorax cylindric and nearly as long as wide, with the
entire elytral apex black. My two examples of puncticollis are
from Guerrero and are males; it has been recently announced by