ART. 28 REVISION OF DISONYCHA NORTH OF MEXICO BLAKE 55 



the ventral surface except the last segment is dark. It is also much 

 more coarsely punctate than colhita, both on the head, pronotum, and 

 elytra, and, as LeConte remarked, it is broader and less oval than 

 collata or xantJiomela^. 1). colJata apparently does not occur west 

 of the Great Plains, and specimens of semicarhonata have been 

 examined only from Colorado and New Mexico. It differs from 

 xanthomelas and triangularis in having a bicolorcd head, and from 

 politula not only in its coloring but also in its punctation. The 

 aedeagus is unlike that of any of the dark colored species. 



This is another species that is rare in collections. I have seen 

 only the LeConte type, a specimen in the Snow collection from Mag- 

 dalena Mountains, N.Mex., and one in the Casej^ collection from 

 Boulder, Colo. 



26. DISONYCHA XANTHOMELAS (Dalman) 



I'LATB 7, Figure 38 



Haltica collar is Illiger, Mag. fiir Insekt., vol. 6, p. 126, 1807 (not Galleruca 



collaris Fabricius, 1798). 

 Hnlticn xanthomelas Dalman. Analecta entoinulogica, p. 79, 1823 (New York). 

 Disonycha xanthomelaeua Gemminger and Harold, Catalogus coleopterorum, 



p. 3497, 1876.— Horn, Trans. Amer. Ent. Soc, vol. 16, p. 209, 1889. 

 Disonycha merdivora Melsheijier, Catalogue, p. 122, 1858. — Gemminger and 



Harold, Catalogus coleopterorum, p. 3497, 1876 (Pennsylvania) (as synonym) . 



Description. — Elongate oval, feebly shining, the head, elytra, 

 mesosternum and metasternum, and legs, except at base, black, the 

 elytra often with aeneous or bluish luster; the prothorax, abdomen 

 in part, and base of legs pale. Head with interocular space about 

 half width of head; carina narrowly produced; a furrow of punc- 

 tures on each side of head extending from fovea near eye down to 

 antennal socket, leaving occiput and front usually smooth and im- 

 punctate, sometimes a few coarse, scattered punctures across front, 

 head entirely dark and polished. Antennae dark with basal joints 

 somewhat paler, third joint shorter than fourth or fifth, which are 

 subequal, the fourth slightly longer. Prothorax approximately 

 twice as wide as long, somewhat convex, without depressions, nearly 

 rectangular with sides slightly arcuate; surface minutely alutaceous 

 and very finely punctate, entirely pale. Scutellum black. Elytra 

 black, feebly shining, with aeneous or bluish luster ; oblong, convex, 

 humeral prominences not marked; surface distinctly alutaceous, 

 punctation fine, not dense. Body beneath pale with black shining 

 mesosternum, metasternum, and legs; the trochanters, base of fem- 

 ora, and often posterior angle of metasternum more or less pale; 

 abdomen pale, sometimes brown in middle; pubescence fine but 

 indistinct. Length, 4.5 to 5.8 mm ; width, 2.2 to 3.4 mm. 



Type locality. — New York. 



