i-i r:i;.\ CAHAIJID.K 519 



1'. crenistriatus LeC. and P. rubripes Zimni., in which the stria- are coarse 

 and punctured, the sutural stria insignificant or obsolescent, and the surface 

 texture a very delicate transverse ribbing nowhere broken up into a 

 reticulation. 



PLATYNUS SENEX. 



I'l. 7, Fit;. 3S. 

 I'latynuH seiier Scmld., Bull. i:. S. Geol. Gcogr. Surv. Terr., IV, 759, (1S78.) 



This species is represented by a single specimen and its reverse. The 

 upper surface is shown with none of the slenderer appendages. The true 

 liinn ot the head can not be determined, as the edges are not preserved. 

 Tin- prothorax is unusually square for a carabid, resembling only certain 

 forms of Bembidium and Platynus, and especially I*, variolatus LeC. It 

 is, however, still more quadrate than in that species, and differs from it in 

 shape, being a little broader than long, broadest just behind the middle, 

 tapering but little anteriorly, and scarcely mure rapidly at the extreme 

 apex; the elytra are together only about half as broad again at base as 

 the thorax, and are furnished with eight very faint and feeble stria-, appar- 

 ently unpunctured, the one next the margin interrupted bv four or five 

 foveai on the posterior halt of the elytra; the humeral region is too poorly 

 preserved to determine the stria- at that point; the form of the elvtra is as 

 in P. variolatus. 



Length of body, (i 1"""; breadth of thorax, Ut mm ; of base of elytra 

 together, 2.3 ram ; length of elvtra, 4.r im . 



Green River, Wyoming. One specimen, Nos. 3998 and 3992. 



PLATYNUS CASUS. 

 I'l. 1, Fi-. L'. 



A single elytron is preserved in the beds which have yielded so man\ 

 I'latvni, which seems to be better comparable with P. rubripes Ziuim. than 

 with any other living form, but better still with the fossil forms from rju- S.IIIM- 

 In-il.s, \\iili \\hich it agrees also better in si/.e, though it is a trill.- l>n>ader, 

 with a considerably more rounded humeral angle, a more rounded outer 

 margin, and tin- iir>t -tna closely approximated to the >nture. Kxcept in 

 tin M- particulars it :igrei-s best with P. halli ; but, somewhat as in P. ruh- 

 ripes though \\ith li--- iv-nlarii v in si/.e and distribution, the interspaces 



