December 1882. BULLETIN BROOKLYN ENTOM. SOC. VOL. V. 57. 
Platycerus, Geof. 
(platys=broad, keras==horn.) | 
Thorax ¢\ Q with side margins equally rounded....... .--. Quereus. 
Thorax of ({‘ strongly, of Q very perceptibly angulate at middle. 
Hind angles of thorax obtuse; mandibles of 5 not denticulated, 
oregonensis. 
Hind angles of thorax distinctly rectangular. 
Mandibles of 9 small acute, slender, elytra finely striate and punct- 
MR UP AIL,” :, . , CaMMmMIPNT a oy MaDe Sane eee e ACA UCS Acagsil. 
Mandibles of Q heavy, stout, very decidedly thickened at middle; 
of °¥\ denticulate near tip, elytra more decidedly punctate and 
SUN EIEN rat eee ee ORO ee eee pete depressus. 
6, querous, Web. Obs. Ent. p. 85. securiidens, Say. Jour .-Ac. Phila: 
III, 1823, p.249. Brown red, shining, hind angles of thorax of ¢ rounded 
and of © obtuse; elytra rugose, deeply punctured. N.Y., Pa., Car., D.C. 
10 to 12 mm. ES 
In thisand the other species of this genus the club of 
antennze equals or exceeds in length joints 2 to 6 inclusive, 
the 2nd joint is always longer than the 3rd while in Lucanus 
the .contrary is universally true—the American species of 
course being only considered. In the ¢ of this species 
the club is very heavy, joints 5 and 6 show a small acute in- 
ward prolongation and are pubescent, without being opaque, 
Fig. 6 joint 7 has the prolongation nearly as long as 8 and 9g 
but much more slender, with 8 to 10 it is opaque pubes- 
cent. The 9 Q in all the species of this genus differs from the q {in 
having only three joints of club pubescent opaque, the terminal 1s more 
rounded, the others are proportionately stouter and less prolonged while 
joint 6 is glabrous and has only a small acute inward prolongation as 
shown in fig. 9, O of @epressus. 
vf oregonensis, Westw. Proc. Ent. So¢. 1844, p. 106, Trans, Ent. Soc. 
yeenon 7p: 277, 0.120, 1, Oy ©, coc@axcens, Lec.) Proc. Ac, Phila. 1861, 
p: 345, Q. Dark-bluish; head and thorax sparsely and roughly punct- 
ured, hind angles of thorax obtuse, lateral margin narrow; elytra punct- 
ured in rows, not rugose; no denticle between- apex of mandibles and 
tooth of inferior margin. Or., Cal.—13 mm. 
