ART. 28 REVISION OF DISONYCHA NORTH OF MEXICO BLAKE 57 



ferred to l\y LeConte is evidently one in Horn's collection labeled 

 " Ga.", and is the only other specimen I have examined. I have not 

 dissected any specimen of oervlcalis, but cannot distinguish it from 

 specimens of xantJwmelas except by the paler coloring of the under- 

 surface. There is considerable variation in size and coloring of the 

 undersurface in the latter species. 



DISONYCHA XANTHOMELAS ATRELLA. new variety 



Plate 7, Figure 39 



Descnption. — Small (4 mm), entirely dark except the prothorax 

 and last 1 or 2 ventral segments. Head shining black, frontal tuber- 

 cles often not at all marked and continuous with the carina; carina 

 narrowly produced; a furrow of punctures extending from fovea 

 on each side near eye toward antennal socket, sometimes scattered 

 coarse punctures across front, head otherwise polished and dark. 

 Prothorax as in typical xanfJwmelas. Elytra oblong oval, shining 

 black W'ithout aeneous luster, the punctation usually finer than in 

 typical xanthome] as. Body beneath finely and indistinctly pubes- 

 cent, entirely dark except prosternum and last ventral segment and 

 margin of penultimate segment, sometimes base of legs slightly paler. 

 Length. 4.2 to 4.8 mm ; width, 2.2 to 2.8 mm. 



Type male and 4 paratypes (1 female, three male). The type and 

 two paratypes in Museum of Comparative Zoology, Cambridge, 

 Mass., Blanchard collection. Two paratypes (male), U.S.N.M. 

 No. 43652. 



Type locality. — Tyngsboro, Mass., collected by F. Blanchard. 



Disfrihvtion. — Massachusetts (Tyngsboro) ; Virginia (Fort Mon- 

 roe, Hubbard and Schwarz collection) ; Alabama (Mount Vernon, 

 H. P. Loding collector). 



Renuu'l's. — At first glance this small dark variety of xanthomelas 

 appears like a distinct species. The head in some specimens has the 

 frontal tubercles undivided by any line or depression from the carina, 

 giving it a most unusual appearance. The aedeagus, however, so 

 closely resembles that of xanthomelas that it is doubtful whether it 

 can be more than varietally distinct, 



27. DISONYCHA TRIANGULARIS (Say) 



Plate 7, Figure 36 



Altica triangularis Say, Journ. Acad. Nat. Sci. Philadelphia, vol. 4, pt. 1, p. 



84, 1824 (Missouri; type lost). 

 Haltica puncticoUis Kirby, Fauna Boreali Amer., vol. 4, p. 218, 1837 (Canada, 



"Lat. 65° "). 

 Disomjcha triangularis Melsheimer, Catalogue, p. 122, 1853.— Crotch, Proc. 



Acad. Nat. Sci. Philadelphia, vol. 25, p. 64, 1873.— Horn, Trans. Amer. 



Ent. Soc, vol. 16, p. 209, 1889. 



