146 ACADE.AIT OF NATURAL SCIENCES 



nee villages on the Platte ; several other specimens, however, 

 occurred during our journey to the mountains. Its color varies 

 from a light chestnut to a black ; but the downy or spiny vesture 

 is immutable, though it is very deciduous. 



It seems to be closely allied to the M. occidentalis ; but if 

 Oliver's description of that insect be correct, it is sufficiently 

 distinct. According to him, that species has sometimes only 

 " une ligne [248] longitudinale, blanche, au milieu du corcelet," 

 and the scutel is " marqu6 de deux taches blanch&tres;" whereas 

 our insect has always three thoracic lines, and but a single scu- 

 tellar spot. 



Mr. Nuttall also obtained specimens of this insect on the Ar- 

 kansas. 



[A species of Polyphylla. — Leg.] 



LUCANUS Lin. 



L. tarallelus. — Mandibles one-toothed ; elytra striate, punc- 

 tured. 



Inhabits the United States. 



L. parallelus Knoch in Melsh. Catal. 



Body dark reddish-brown, with dilated punctures: mandibles 

 with an elevated conic tooth arquated inwards, situated on the 

 middle of the superior inner edge, and a smaller tooth on the 

 middle of the inferior inner edge; elytra punctured, striate, striae 

 with much dilated punctures; humeral angle mucronate ; tibiae, 

 anteriors from four to seven-toothed, interior and posterior ones 

 one-spined on the middle. 



Length four-fifths of an inch. 



Female destitute of the tooth of the mandibles. 



Very distinct from L. parnJldllpedus by the striated elytra. It 

 is not uncommon in the Atlantic States, and as far west as the 

 Rocky Mountains. 



[Belongs to Dorcus. — Lec] [249] 



PLATYCERUS Latr. 

 P. SECURIDENS. — Mandibles at tip securiform, and about six- 

 toothed ; elytra striate. 



Inhabits the United States. 

 Lucanus platyccrxis Melsh. Catal. 



[Vol. III. 



