CERAMBYCIDyE 373 



extended than supposed, the only point to be mentioned being the 

 fact that species or subspecies, whatever may be the meaning of the 

 latter term in my own opinion largely without meaning in our 

 present stage of knowledge are, as in Tetraopes, very much more 

 numerous than hitherto admitted. A genus such as these must 

 either be an undecipherable chaos of few arbitrary composite units, 

 or a systematic succession of a greater number of more clear-cut 

 units, until the limits of variability become really known. I prefer 

 the latter manner of solving the difficulty, provided there be any 

 structural basis for the finer subdivisions. 



There are even more unaccountable eccentricities of color varia- 

 tion in Mecas per grata than in any Oberea that I have seen; for ex- 

 ample, in one male before me the fifth ventral segment is wholly 

 black, while in another male from the same locality and apparently 

 not differing in any other way, the fifth segment is bright red, the 

 basal black part separated by an abrupt line. In the Oberea 

 bimaculata series, I find that in some species the head may be as 

 pale as the prothorax to nearly black, but in the latter case the dark 

 color is nubilous and not of a deep black and separated from the 

 pale basal part by a sharp line of demarcation, as it is in some allied 

 but apparently distinct species. The coloration of the legs, men- 

 tioned above under exilis, like that of Parallelina subargentata, is 

 another unexplainable instance of color dimorphism I would rather 

 use this term than variability in such cases for it does not seem to 

 be sexual in origin. Of course I may have confused two different 

 taxonomic units, which however seems inconceivable, either in this 

 case or that of Mecas pergrata. 



Tribe TETRAOPINI. 



This tribe, as organized by Bates, seems to be sufficiently distinct 

 from the Phytoeciini by reason of the very broadly and completely 

 divided eyes. The three genera known to me are Tetraopes, 

 Phiza and Tetrops. 



Tetraopes Serv. 



In North America, as far to the southward as Central America, 

 this is a large genus of peculiarly massive longicorns, frequently 

 closely allied among themselves but at the same time exhibiting 

 considerable diversity, especially in ornamentation and vestiture. 



