278 MEMOIRS ON THE COLEOPTERA 



Upper surface opaque; head without more than a feeble longitudinal 

 elevation; anterior tibiae tridentate externally Group I 



Upper surface shining, the head with a distinct longitudinal elevation; 

 anterior tibiae with a single feeble external tooth at about apical 

 third Group 1 1 



The second of these groups is represented by a single species, so 

 far as known, while of the first probably at least two hundred exist 

 in collections. I find among my tropical representatives some 

 inconstancy in the dentition of the anterior tibiae; these are gen- 

 erally clearly tridentate, but in four species marked insculpta, apiata, 

 albiventris and multipunctata, from Colombia and Brazil, they have 

 no external tooth except the slender acute apical process and their 

 outline is remarkably surate, a form which however does not differ 

 .essentially from the minutely tridentate tibiae of liturata; in another, 

 labeled braziliensis, they are still more aberrant, having an external 

 tooth just beyond the middle but no other, except the apical, 

 which is very stout, with rather deeply, strongly and acutely bifid 

 apex possibly a sexual character. It would seem from various 

 points of view, that the Gymnetids stand in urgent need of general 

 revision, for there must be many other aberrant forms besides 

 these and the divisions made by Burmeister. 



Group I. 



Subgenus Gymnetis in sp. 



In the following tabular statement I have included the Mexican 

 and Central American chevrolati and cinerea sections of the subgenus, 

 as I have what appear to be a number of distinct taxonomic forms 

 belonging to them, that have not been characterized heretofore. 

 The chevrolati section is evidently a part of that containing our 

 common sallei, and in the extended intervening geographic region 

 analogous forms occur quite frequently. It is necessary to include 

 the cinerea section, for argenteola Bates, forming a part of it, 

 comes within our territories: 



Upper surface opaque, black or blackish, margined externally with straw- 

 yellow, either throughout or on the elytra alone, the yellow margin 

 usually prolonged internally at one or more points .2 



Upper surface similarly velvety-opaque but almost perfectly uniform in 

 tint throughout, and of various shades of ochraceous, olivaceous or 

 greenish-gray; body smaller, narrower and still more depressed as a 

 rule; mesosternal process nearly flat, obtusely rounded at tip and 

 almost horizontal 4 



