Casey — A Revision of the American Paederini. 161 



except that they are transverse, only very slightly narrower than the 

 prothorax though much shorter. Length 3.2 mm.; width 0.45 mm. 

 Virginia, — Mr. Ulke augnstum n. sp. 



The gular sutures are widely separated, most narrowly so 

 well to the front, rapidly diverging toward base and are gen- 

 erally subobliterated. The male sexual characters are feeble, 

 the fifth ventral segment unmodified, the sixth having a 

 rounded apical sinuation occupying almost the entire tip, 

 rather more than three times as wide as deep, with the edge 

 of the sinus concavely beveled, gradually more broadly so 

 around the bottom of the sinuation. 



Medon Steph. 



As far as known at present, the genus Medon is confined to 

 the western part of the continent, with the exception of the 

 very small texanum, which occurs in Texas and americanum, 

 which appears to inhabit the Atlantic slope exclusively. The 

 west coast species are much larger than the European fuscu- 

 lum and are generally very finely punctate, sometimes densely 

 so and dull in lustre, while in the eastern americanum, the 

 sculpture is comparatively coarse, much as in the palaearctic 

 species mentioned.* The species are far less numerous than 

 those of Paramedon, which largely replaces the European 

 genus in America, and those before me may be recognized by 

 the characters outlined in the following table: — 



Elytra small, nearly as in fusculum, never materially larger than the pro- 

 thorax; eyes very small; species confined to the Pacific coast regions.. 2 



Elytra large, notably larger than the prothorax; species distributed through- 

 out the United States, frequently associated with ants 8 



2 — Body pale, castaneous or testaceous in color 3 



Body black or blackish, the under surface of the head concolorous 6 



* I have adopted the neuter ending for specific names in this and allied 

 genera for the sake of constancy and uniform law in scientific nomenclature, 

 holding that all generic names ending in m or n should require the neuter 

 ending, in conformity with the general rule of the Latin language, and, in 

 like manner, that all names ending in is or a should be feminine and all in 

 os or ms masculine, not even excepting such a name as Venus. In other 

 words it is the form of the word which should be considered, when used as 

 a generic symbol, and not its meaning in the original tongue. 



