SCUDDER ON FOSSIL INSECTS. 759 



without the irregularities which mark the furrow formed by the margin- 

 ate outer edge in this species and its near allies. The elytra are almost 

 precisely similar in form to those of C. angusticolUs, but they are slightly 

 broader at the base ; they are covered with ratber inconspicuous, closely 

 crowded striee, almost exactly as in the recent sjjecies mentioned, but 

 even more closely crowded, numbering about twenty-five, including the 

 frequent lines bordering the margin, which is simple and striate to the 

 very edge, or, possibly, faintly marginate, as in somei Garahi, but diifer- 

 ing conspicuously from the species of Cychriis to which I have compared 

 it. The form of the tip of the elytra is also exactly as in this species. 

 The interspaces of the elytra do not exhibit the imbricated appearance 

 common to most of the Carabini, but the surface has more of the nearly 

 imperceptible waviness seen in C. angusticolUs, although, if anything, the 

 surface is less broken. 



Length of elytron 7.5™™; greatest breadth (behind the middle) 2.G""". 



Platynus senex. — This species is represented by a single specimen and 

 its reverse (Nos. 3998, 3992). The upper surface is shown with none of 

 the slenderer appendages. The true form of the head cannot be deter- 

 mined, as the edges are not preserved. The prothorax is unusually 

 square for a Carabid, resembling only certain forms of Bembidium and 

 Platynus, and especially P. variolatus LeO. 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 more rapidily 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 stride, apparently un- 

 punctured, the one next the margin interrupted by four or five fovese 

 on the posterior half of the elytra ; the humeral region is too poorly 

 preserved to determine the striae at that point ', the form of the elytra 

 is as in P. variolatus. 



Length of body 6.1""" ; breadth of thorax 1.5""", of base of elytra together 

 2.3""" J length of elytra 4.1"'">. 



HYDEOPHILID^. 



Tropisternus saxialls. — One specimen and its reverse (Nos. 4023, 4027), 

 found by me in the Green River shales, represent a species of Tropi- 

 sternus nearly as large as T. hinotatus Walk, from Mexico. The large 

 size of the head and the shortness of the prothorax are doubtless due to 

 the mode of perservation, the whole of the head, deflected in life, being 

 shown, while the thorax is in some way foreshortened. In all other re- 

 spects, it agrees with the Eydrophilidce, and especially with Tropisternus, 

 having the form of the species mentioned. The head is broad and well 

 rounded, with small, lateral, posterior eyes. The thorax is much broader 

 and much more than twice as broad as long, with rounded sides, taper- 

 ing anteriorly, the front margin broadly and rather deeply concave, the 



