NORTH AMERICAN COLEOPTERA. 177 



From the description which Chapuis gives of this insect under 

 the name Pachyonychis (Genera xii, p. 100) it is very evident that 

 he has not seen the insect, otherwise it would never have been placed 

 in the Monoplati from the oi)en front coxal cavities. With the 

 limited material in our ftiuna it is better to place the genus with the 

 CEdionyches, although it might well constitute a tribe intermediate 

 between that and Monoplati. The fact of the dissimilarity of the 

 claws seems to have escaped notice, those of the hind tarsi being ab- 

 solutely simple and slender, those of the front and middle are slightly 

 appendiculate in the usual manner. This fact is sufficient to indicate 

 the tribe, together with the dissimilarity in the forin of body from 

 any of the CEdionyches, approaching somewhat certain Monoplati as 

 Tetragonotes. 



The reasons for adopting this name for the genus have been fully 

 given by Mr. Jacoby, who has also shown the incorrect position of 

 the genus by Chapuis (Trans. Am. Ent. Soc. 1888, p. 302). 



H, diinidiaticornis Crotch. — Elongate oval, subdepressed, feebly shin- 

 ing, beneath almost entirely piceons. legs yellow, above black, elytra blue-green 

 Antennse a little longer than half the body, the three basal and half the fourth, 

 also the three terminal joints pale, the intermediate piceous. Head black, 

 smooth, frontal tubercles distinct and with a transverse depression above them. 

 Thorax a little wider at base than long, narrower in front, apex scarcely emar- 

 ginate, sides obtusely angulate at middle, the margin very narrow, front an- 

 gles not dentiform, base sinuate each side, the hind angles moderately prominent, 

 surface black, shining, not punctate. Elytra wider at base than the thorax, 

 humeri rounded, umbone distinct, limited within by a slight depression, surface 

 bluish green, relatively coarsely and closely punctate, but much smoother near 

 the apex. Body beneath black. Abdomen piceous, the last segment yellow. 

 Legs pale yellow. Length .13 inch. ; 3.25 mm. Plate VI, fig. 9. 



The specimen before me is a male, and has the last segment sub- 

 truncate and with a slight impression at middle, in length the seg- 

 ment nearly equals the two preceding, and in the female is probably 

 longer. 



This insect seems to be one of the rarest of our Halticides. I have 

 seen but three specimens, — one in my cabinet and that of LeConte, 

 from Georgia, the third in the British Museum from an unknown 

 locality. As the latter came from the Dejean collection it is prob- 

 ablv also from Georgia. 



TRANS. AM. ENT. .SOC. XVI: (23) MAY. 1889. 



