112 LE CONTE.— LONGICORN COLEOPTERA. 



3. M. DASYSTOMA. — Depressa, nigro-picea, nitida, capite varioloso, fronte transtersim valde impresso, thorace 

 lateribus parallelis serratis, confertissime punctulato, plaga utrinque ante medium quadrata, altera 

 transversa basali lineisque duabus utrinque versus latera laevigatis; elytris impunctatis; mandibulis 

 capite vix brevioribus, intus cum labro dense fulvo-villosis. Long. -8 — 1"75. 



Hald. 31. 



Prionus dasystomiis, Say. J. Ac. Nat. Sc. 3, 326. 



Malhdon melanopus, Hald. 30. (var. maior.) 



Georgia and Missouri. The thorax is less convex than in the preceding species, 

 rounded at the base, with obtuse posterior angles ; the facets are usually entirely 

 smooth, but sometimes are marked with a few large punctures ; the two lateral lines 

 are scarcely elevated; the exterior one very short and oblique ; it is farther removed 

 from the margin than in M. costulata. The mandibles are very thick at the base 

 and acute at the apex, with a wide prominence near the middle ; between these points 

 are one or two very indistinct teeth; the subocular tubercle is obtuse and widely 

 emarginate exteriorly. I have not yet found any sexual characters. 



A closely allied Mexican species, (Prionus maxillosus, Fabr.,) has longer mandibles, 

 less thick at the base, more strongly carinated above, and armed with much stronger 

 teeth : the front is scarcely impressed. 



