420 REVISION OP THE ELATERIDa: 



B. Tarsi articulo 4'° ?2cc htiore ncc lohato. 



4. M. humeralis, opacus, atcr, parce fusco-pubescens, thorace latitudine breviore, lateribus 

 parallelis apice sumina rotundatis, angulis pusticis subcarinatis, linea marginali dislocata, confertiin 

 scabro-punctato, medio utrinque subfoveato, elytris fere parallelis apice obtusis confluenter scabro- 

 punctatis, obsolete striatis, basi late rufescentibus, pedibus antennisque rufis, bis articulo 3 i0 non an- 

 gustiore. Long. -15. 



Lee. Proc. Acad. Nat. Sc. G, 48. 



JSucnemis humeralis Say, Trans. Am. Phil. Soc. 6, 189; Harris, Trans. Hartford Soc. Nat. Hist. 72. 



Pennsylvania, Dr. Melsheimer; Tennessee, Dr. Schaum. Differs from all the preceding 

 species by the third joint of the antennas being as wide as the fourth. The antennas in 

 both specimens are half as long as the body, compressed, but not strongly serrate: the 

 two discoidal foveas of the thorax are broad, but not deep; there is also a trace of a dorsal 

 impressed line: the marginal line is dislocated, as usual ; the anterior portion is very short, 

 and the posterior portion extends nearly to the apex. The claws of the tarsi appear to 

 be indistinctly toothed at the middle. 



This species seems subject to variation in colour: the anterior margin of the thorax and 

 the posterior angles are usually tinged with rufous. A specimen sent by Dr. Schaum has 

 the elytra entirely black, but otherwise seems not to be sufficiently distinct. 



Div. 3. CEROPHYTIDES. 



Although differing greatly from each other, there is such a close accordance in some 

 characters between Cerophytum and Perothops that I have been induced to place them 

 together. The latter genus has been very fully examined by Erichson, and the detail of 

 his observations is given in the third volume of Germar's Zcitschrift. He has placed it 

 among the genuine Elateridas, considering it as forming a transition to the Cebrionidte by 

 its more prominent mandibles and cleft ligula. The approximation of the antenna), how- 

 ever, brings it nearer to the Eucnemides; and it will be found, on comparison, that those 

 points in which it differs from the Eucnemides are precisely those in which it differs from 

 the true Elateridcs, and approaches the Cebrionides. I therefore prefer regarding it as an 

 osculant between the latter family and the Eucnemides, and, on account of its general 

 form, and the structure of the head, to be placed next the last mentioned division. 

 The differences between Cerophytum and Perothops are as follow: 

 The front of Cerophytum is gibbous, while in Perothops it is only dcflexed anteriorly. 

 The mandibles are larger and more prominent in Perothops: the presternum is furnished 

 with a short rounded lobe in Cerophytum, while in Perothops it is nearly truncate ante- 

 riorly: the lateral suture is curved convexly outwards in Cerophytum, and is straight in 

 Perothops: the laminae of the posterior coxa> arc somewhat suddenly dilated internally in 

 Perothops, and are entirely obsolete in Cerophytum: the posterior trochanters arc very long 

 in Cerophytum, and moderate in Perothops: the tarsi arc lobed and spongy in Cerophy- 

 tum, with the first joint longer and the fourth joint bilobed: in Perothops the joints are 

 short, diminish very gradually in length, the first being much thicker, and are very densely 

 pubescent. 



