312 G. H. HORN, M. D. 



acute, slightly divergent and distinctly carinate. Elytra convex, robust, nar- 

 rower at base than thorax gradually broader behind the middle, apex obtuse ; 

 surface striate, striae deeply punctured, intervals flat with punctures sparsely 

 imd irregularly placed each bearing a hair. Body beneath somewhat darker 

 in color than the upper surface and pubescent. Prothorax beneath punctured 

 as above. Abdomen finely punctured with very minute punctures intermixed, 

 last segment more decidedly opaque. Legs pale yellowish testaceous, fourth 

 tarsal joint with lobe very small and robust. Length .22 — .30 inch; 5.5 — 7.5 

 mm. 



This species resembles in many of its characters, M. sordidus, Lee. 

 but may be known by its more robust form. The fourth tarsal joint 

 of the latter species lias a long lobe nearly equalling half the fifth 

 joint. Both species should be referred to Section III, Candeze, or if 

 the genus Heteroderes, should be thought worthy of preservation, JM. 

 xordidiis, Lee, should be placed near ampJicolUs^ from the presence 

 of a fine carina, within the main carina of the hind angles and M. ro- 

 linstus, Horn, from the absence of this character near muscuhis. The 

 sole character on which Ueteroderes is founded consists in the peculiar 

 sculpture of the thorax in which the'large punctures are rather regu- 

 larly placed over the entire surface while between are very minute 

 punctures so densely placed as to make the surface appear opaque. 



Abundant at Camp Grant, Arizona. 



M, mutuus, n. sp. — Brown sub-opaque, oblong, convex, sparsely clothed witli 

 yellowish-grey hairs. Head coarsely but sparsely punctured. Antennpe 

 sliorter than head and thorax, second and third joints sub-equal, together 

 nearly equal to the fourth. Thorax longer than wide scarcely narrowed in 

 front, sides very feebly rounded, very slightly sinuate near the hind angles 

 Avhich are scarcely divergent but acute and distinctly bicarinate, the outer 

 carina acute prolonged nearly half the length of thorax and near the margin, 

 the inner carina short scarcely half the length of the angle ; disc more convex 

 than usual in our species and with coarse equal punctures rather closely placed. 

 Elytra as broad as thorax, convex, sub-parallel in front, slightly narrowed and 

 obtusely rounded at apex, surface striate, striae punctured, intervals flat punc- 

 tulate anal obsoletely reticulate. Body beneath colored as above, sparsely punc- 

 tulate. Legs testaceous. Length .50 inch; 12.5 mm. 



This species is rather more convex than any other in our fauna al- 

 though not as robust as (lurt'fus and its allies, being four times as long 

 as wide. The lobe of the fourth joint is very narrow and very short 

 even more so, proportionately than in miritus. The bicarination of 

 the hind angles is here very distinct, but is not unique in the genus, 

 as the same may be seen in liuidus. 



The specimen kindly loaned by Mr. UIke, is from Arizona, probably 

 near Fort Whipple. 



