20 NATURAL HISTORY BULLETIN 



Aleocharini as Atheta, which genus is well represented in North 

 America today. The impressions on the pro- and mesothorax 

 probably have to do with the coxa, but I have not felt safe in 

 describing them as such. 



Lathrobium Grav. 



L. ANTEDILUVIANUM n. sp. (Plate III, Figs. 2, 3.) Form rather stout for 

 this genus. Head much larger than the prothorax, almost regularly ellip- 

 tical in outline, sculpture not distinct, but there seems to be indications of 

 coarse scattered punctures. Eyes small, elliptical, anterior in position. An- 

 tenna only about as long as the head, first joint long, the others short, 

 second and third longer than those following, eleventh (possibly through 

 decomposition) subtruncate at the tip. Prothorax narrow, subelliptical, 

 sculpture indistinct. Elytra short, only a little longer than the prothorax, 

 sculpture not defined. Abdomen badly decomposed, but the form is evi- 

 dently nearly parallel to the vicinity of the apex. Legs short and stout, the 

 tibiae broad. Length, 9.60 mm. 



As far as appearance goes, except for the structure of the 

 antennae and legs, this might be a Cryptohium. It seems to go 

 better in Latlirohimn, in the wide sense, but is not especially 

 like any of our recent forms. The short elytra recall those of 

 L. hrevipeime, which, however, has the hind angles of the head 

 less rounded. 



P.^DERus Grav. 



P. ADUMBRATUS n. sp. (Plate IV, Figs. 4, 5.) Form elongate. Head 

 smaller than usual in this genus, antennae proportionately longer than in 

 most of the Florissant fossil Staphylinidte, second joint not reduced. Pro- 

 thorax pyriform in outline, strongly narrowed behiiid. Elytra one-third 

 longer than the prothorax, truncate apically. Abdomen one-fourth longer 

 than the remainder of the body. Legs rather slender, but short, the tibiae 

 not at all expanded. Length, from front of prothorax to abdominal apex, 

 4.65 mm. 



This is about the size of the recent species which passes in 

 collections as P. littorarius Grav., but the fossil seems to be more 

 slender and to have a rather smaller head. As in the other 

 Florissant Staphylinidfe, the legs are short compared with pre- 

 sumed generic representatives of recent times. The difference in 

 the breadth of the right and left antennas, as shown in the sketch, 

 is probably due to their varying position in reference to the 

 normal plane. 



