CERAMBYCID.E 345 



uniting longitudinally by an angular extension of the anterior 

 of the two and not the posterior, the longitudinal distance be- 

 tween 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 punc- 

 tate, 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- 

 ing the Mexican puncticollis and angustlcollis , which relate ob- 

 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 



