Casey — A Revision of the American Paederini. 161 
except that they are transverse, only very slightly narrower than the 
prothorax though much shorter. ehiestic 3.2 mm.; width 0.45 mm. 
Virginia, — Mr. UlKe.... cece cece ese emeceses ae - -angustum nN. 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,.......e.ee.0- 8 
2— Body pale, castaneous or testaceOus in COOL. ...eesececseccesccerees B 
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 ora should be feminine and all in 
os or us 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. 
