PKiESTUS.— NEOBEOTICA. 571 



body, tapering towards the apex, the third and following joints nearly equal in length ; thorax about two 

 and a half times broader than long, the sides straight, the angles obtuse, the disc transversely depressed 

 at the middle, shining, testaceous, not visibly punctured ; scutellum broad, nearly subquadrate, its apex 

 broadly truncate ; elytra very dark bluish-black, opaque, extremely finely rugose. 



Hal. Panama, Volcan de Chiriqui {Champion). 



*** Tibiae mucronate ; claws bifid. 

 TRIARIUS. 



Body elongate ; antennae filiform, the second and third joints short and nearly equal ; thorax transversely 

 subquadrate, without depression ; elytra irregularly punctured, their epipleurse very narrow and visible 

 at the base only; tibiaa armed with a spine ; the first joint of the posterior tarsi as long as the following 

 two joints together ; claws bifid, the inner division rather short ; anterior coxal cavities open. 



The almost invisible elytral epipleurse place Triarius near Phyllobrotica and Phyl- 

 lechthrus, from both of which the armed tibiae and bifid claws separate it. The spine at 

 the apex of the posterior tibise is long and very distinct. 



I place a single species from Northern Mexico in this genus. 



1. Triarius mexicanus. 



Testaceous, the head, the basal three joints of the antennae, the thorax, and legs fulvous ; elytra scarcely visibly 

 punctured, testaceous ; breast black. 



Length 2-3 lines. 



Head not visibly punctured; the frontal tubercles transversely trigonate ; clypeus narrowly transverse; 

 antennse black, the first three joints fulvous, the third joint scarcely longer than the second ; thorax 

 transverse, about one half broader than long, narrowed towards the base, the sides nearly straight, 

 the surface not visibly punctured; scutellum black or piceous ; elytra extremely finely and closely 

 punctured, the rest of the surface (when seen under a very strong lens) very finely granulate and slightly 

 rugose ; legs robust ; all the tibiae armed with a spine, the spine long and very distinct on the posterior 

 pair ; the last abdominal segment in the male truncate in the middle, deeply sinuate at the sides. 



Eab. Mexico, Northern Sonora {Morrison). 



**** Tibice mucronate ; claws appendiculate. 

 NEOBROTICA. 



Body elongate ; antennse filiform, the third joint generally long and slender ; thorax subquadrate, more or less 

 deeply transversely sulcate, the sulcation not extending to the sides ; legs slender ; tibiae mucronate ; the 

 first joint of the posterior tarsi as long as the following three joints together; claws appendiculate ; the 

 anterior coxal cavities open. 



Neobrotica has entirely the appearance, and in many instances the elytral pattern, of 

 Diabrotica. It might be easily mistaken for that genus, unless the claws are examined, 

 these being appendiculate in Neobrotica (instead of bifid as in Diabrotica) ; with this 

 character a deeply sulcate thorax is generally combined. Several species described 

 here offer a striking instance of so-called "mimicry" in regard to the colour and 

 markings of the elytra (and indeed of the antennse also), and in this respect agree in 

 every particular with some forms of Diabrotica. As I have in several cases both sexes 



4d2 



