DIPHAULACA. 265 



I separate this species from its congeners on account of the close punctuation of the 

 elytra, which is rather obsoletely arranged in rows. The typical character of this species 

 is not so pronounced as usual ; the frontal tubercles are, however, very distinct, the 

 carina is very short, and the anterior angles of the thorax are equally pointed, although 

 not produced outwards. The basal elevation and punctuation of the elytra show the 

 place of the insect to be in this genus, of which I know no species with such closely 

 punctured elytral striae. I may add here that Clark, in his paper on the American 

 Halticidee, describes one or two species which he compares to D. punctata and D. con- 

 tempta. No such species as these latter ones have ever been described under such 

 names to my knowledge. 



4. Diphaulaca nitida. 



Ovate, widened behind, very convex, dark metallic violaceous bine ; thorax impunctate, transversely and 

 longitudinally grooved. Elytra with deep basal depression, finely punctate-striate, apex nearly im- 

 punctate. 



Length 2-3 lines. 



Head impunctate, the frontal tubercles distinct, well limited, and rather elongate ; carina short, but distinctly 

 raised ; palpi slender ; antennae nearly two thirds the length of the body, third and fourth joints equal, 

 the former twice as long as the second joint, obscure bluish violaceous, closely pubescent ; thorax trans- 

 versely convex, anterior angles acute and slightly produced outwards, sides rounded at the middle ; the 

 basilar groove deep and sinuate at the middle, its sides limited by a deep longitudinal groove ; surface 

 entirely impunctate, very shining and smooth ; scutellum with the apex rather rounded ; elytra widened 

 behind the middle, very convex, the base swollen and transversely depressed below this elevation ; surface 

 finely, closely, and rather regularly punctured, the apex nearly impunctate in many specimens. 



Var. Above metallic yellowish green. 



Hab. Mexico, Jalapa, Cerro de Plumas (Roge), Santecomapan, Teapa, Cordova (Salle) ; 

 British Honduras, river Sarstoon (Blancaneaux) ; Guatemala, San Geronimo, Capetillo, 

 Purula (Champion) ; Costa Eica, Volcan de Irazu (Rogers). 



The species described here is one of the most puzzling insects of the genus in which 

 I have placed it, on account of the projecting anterior angles of the thorax, which also 

 has a deep transverse and longitudinal groove, and of the distinctly raised basal portion 

 of the elytra. The amount of variability exhibited by the very numerous specimens 

 before me makes it impossible to come to any even approximate conclusion as to the 

 specific value of the characters to be found. The description given above can only be 

 used as a general guide, to which I will add that shape, comparative length of the joints of 

 the elytra, sculpture of the latter, and general form of the insect are scarcely alike in 

 two specimens even from the same locality, which I consider of more importance in the 

 separation of forms than even their outward appearance. I may, however, remark that 

 nearly all the Mexican specimens are of a dark violaceous blue colour, and the Guate- 

 malan and Costa-Eican insects of a yellowish metallic green, although specimens of a 

 blue colour occur also amongst those from the last-named localities. From Jalapa and 

 Costa Eica I have before me small and larger specimens more or less convex, with stout 

 or more elongate antennae, and elytral punctuation as variable, which would necessitate 



biol. CENTE.-AMER., Coleopt., Vol. VI. Pt. 1, February 1884. 2 m 



