NORTH AMERICAN COLEOPTERA. 211 



The species is remarkable in the color of the antenna;, the four 

 basal joints are pale, also the two terminal in specimens from Texas, 

 and but one in a specimen from Lower California in Mr. Ulke's 

 cabinet. 



Occurs in Texas and the Peninsula of California. 



16. D. politnia u. sp. — Oblong oval, slightly depressed, surface very shiu- 

 iug. Anteause slender, half the length of body, piceoiis, underside of three 

 basal joints paler. Htad shining, occiput blue-black, front yellow, labrum black, 

 frontal carina very obtuse, tubercles distinct, a few coarse and deep punctures 

 near each eye. Thorax pale yellow, immaculate, twice as wide as long, narrower 

 in front, sides feebly arcuate, margin narrow, disc finely, spar.sely and indistinctly 

 puuctulate. Elytra a little wider at base than the thorax, humeri distinct, um- 

 boue moderate, a slight depression within it, surface bright cobalt-blue, shining, 

 distinctly, but rather densely not coarsely punctate. Prothorax beneath yellow, 

 metasternum black Abdomen piceous at middle, widely bordered with yellow, 

 the surface shining, coarsely, not closely punctate, the pubescence scarcely evi 

 dent. Anterior and middle femora yellow, the upper side more or less piceous, 

 the tibiae and base piceous. Posterior femora yellow at base, piceous at apex, 

 the colors diagonally separated, the tibise and tarsi piceous. Length .20 inch. ; 

 5 mm. 



Among the species in the series with elytra more oi- less blue this 

 may be known by the very distinctly punctate elytra. The colors 

 are very constant; the posterior femora have the colors separated 

 diagonally, so that the underside is more yellow, while the upper is 

 more black. 



Occurs in New Mexico and Arizona. 



17. D. niellicollis Say. — Oval, similar in form and color to xnnthomelsena. 

 Antenuse half as long as the body, piceous, the three basal joints pale in front, the 

 joints very gradually shorter from the fourth to tenth, eleventh longer. Head 

 blue black between the eyes and posteriorly, front yellow (labrum piceous), a few 

 coarse, deep punctures near each eye. Thorax pale yellow, twice as wide as long, 

 narrowed in front, sides feebly arcuate, margin very narrow, disc regularly con- 

 vex, extremely finely alutaceous, impunctate. Elytra a little wider at base than 

 the thorax, humeri distinct, but obtuse, umbone not prominent, surface dull blue, 

 very finely alutaceous, and with very indistinct, fine, sparse punctures. Pro- 

 thorax yellow beneath, raetathorax piceous, abdomen piceous at middle, with 

 the apical segment and wide lateral border yellowish, the surface moderately 

 closely punctate, pubescence indistinct. Femora entirely yellow, tibife piceou.s, 

 paler at base, tarsi piceous. Length .18— .20 inch. ; 4.5—5 mm. 



This species is doubtless mixed with xanthomelfp.na in most collec- 

 tions, due to the hasty aggregation of a number of well defined spe- 

 cies under one name. It is remarkable that the descri|)tion bv Say 

 seems to have been lost sight of in our literature, as the same species 

 has been redescribed by LeConte as semicarbonata. 



