AMERICAN COLEOPTERA. 137 



Elytra black. Antennse and part of epistome yellow. 



Third joint of antennjB % , broadly triangular, succeeding 

 joints strongly transverse, almost pectinate. Legs all 



'yellow scaber Ilald. 



Third joint of antennae '^ , nearly cylindrical, slightly 

 compressed, succeeding joints longer than broad. Hind 



legs, or at least femora black concolor Lee. 



Elytra yellow. Antennaj, whole of palpi, and front, dark.... flavipennis Horn. 



Oar species of Mijctcru^ are found each within a very distinct fau- 

 nal rei:ion ; scoher bein^' eastern, concDlor to that central region of the 

 extreme west, bounded on the west by the Sierra Nevada range, while 

 Jiavipcnnis is essentially a west coast insect. The characters given in 

 the preceding table will enable theui to be recognized when found. 



M. CONCOLOR Lee. occurs abundantly at Keyesville, Cal., and may 

 be found on the flowers of the Aescuf as (Buckeye). 



MECYNCTARSUS Ferte'. 

 M. delicatulus, testaceous, moderately elongate, clothed with whitish silken 

 pubescence. Thorax broader than long, narrower behind, sides broadly rounded, 

 posterior angles scarcely distinct, horn elongate, margin very coarsely dentate, 

 crest distant from margin, narrow and serrate in front, and with a longitudi- 

 nal fine ridge. Elytra oval, humeri broadly rounded, suture and common cen- 

 tral spot dark brown or black. Length .10 inch (horn included). 



Two specimens from Fort Yuma, collected by Capt. Jno. E. Hill. 



The horn is about two-thirds the length of the thorax, its margin 

 very coarsely dentate. The crest occupies the middle third of the horn, 

 and is itself finely serrate, and encloses a fine longitudinal I'idge. Be- 

 tween the crest and the margin of the horn, in front, are some shining 

 granular elevations. 



Meci/notajsus diff"ers froin Kofoxna in having the hind tarsi longer 

 the tibias, and the penultimate joint not bilobed. The pubescence is 

 finer, more dense and recumbent than in A^otoxus. Our species ap- 

 pears to agree with the European in having the humeri not distinct, 

 but broadly rounded. It is entirely testaceous in color except the su- 

 tural margin, and an oval spot at the middle of the suture, which are 

 nearly black. 



EHINOPLATIA, n. g. 

 Mentum subquadrate, anterior angles rounded, apes truncate, and 

 with two grooves and distinct median ridge slightly bifurcate in front, 

 gular peduncle very prominent, rounded in front, fitting the basal 

 emargination of mentum, ligula trapezoidal, coriaceous, emarginate in 

 front. Last joint of palpi narrowly triangular, maxillary palpi long. 

 Mandibles elongate, arcuate at tip and acute. Labrum elongate, quad- 



TRAN.S. AMER. ENT. SOC. (18) AUGUST, 1S68. 



