428 bulletin: museum of comparative zoology. 



Philhydrus scudderi Wickham. 



Represented by one specimen, No. 2,436 M. C. Z. (No. 9,712 S. H. 

 Scudder Coll.), slightly smaller than my type but exhibiting almost 

 exactly the same proportions in length and breadth. It measures 

 4.50 mm. in length and 2.25 mm. in width. 



Hydrobius titan Wickham. 

 One specimen, No. 2,437 M. C. Z. (No. 10,411 S. H. Scudder Coll.). 



SILPHIDAE. 



SiLPHA beutenmuelleri, sp. nov. 

 Plate 1, fig. 3. 



Described from an elytron only, which is apparently a little broken 

 at apex and much more so at base, but judging from the costae is 

 approximately of its full original length. Sutural margin with well- 

 defined bead, disk sharply tricostate, the costae nearly straight, 

 slightly convergent apically, subequidistant, the inner separated from 

 the suture by a distance markedly greater than the intercostal width. 

 The outer costa, at middle, is about three fourths as far from the outer 

 margin as from the suture, while exterior to it and separated from it 

 by a space about equal to that between the suture and the inner costa 

 is a deep groove extending the entire elytral length. Apex probably 

 bluntly rounded. Punctuation well defined over nearly the entire 

 surface, the punctures sharp and rather distant, finer at apex and 

 (possibly on account of the state of preservation) not distinguishable 

 exteriorly to the lateral groove. Length a trifle over 10 mm. 

 The single specimen is without counterpart. 



Type.— No. 2,438 M. C. Z. Florissant, Col. (No. 5,111 S. H. Scudder 

 Coll.). 



At first, I had intended to refer this elytron to Necrodes primaevus 

 from these shales. In length, the elytra of the two differ only about 

 1 mm., but the description of N. primaevus states that "except for the 

 much shorter elytra it is difficult to separate this species by any tangi- 

 ble characters from the living N. surinamensis." It seems unlikely 



