Casey — A Revision of the American Paederini. 247 
for a short distance to the rather broadly arcuato-truncate base; pro- 
thorax less than three-fifths as wide as the head, distinctlyJelongate, the 
sides subangularly rounded at apical two-fifths, the base nearly twice 
as wide as the apex, the surface slightly elevated along the middle; 
elytra quadrate, parallel, as long as wide, equal in width to the head, 
slightly longer than the prothorax and very much wider, the surface 
rather depressed, somewhat coarsely, very densely, rugosely and granu - 
larly punctate, the suture not at all margined; abdomen at base as 
wide as the elytra, still more coarsely, closely and rugosely punctate, 
the last two segments becoming much more finely so and with the side - 
margin greatly reduced, the segments not impressed at base. Male 
with the fifth ventral unmodified, the sixth with an abruptly formed, 
subparabolic emargination, deeper than wide, about a third as wide as 
the apex, with its bottom broadly rounded; ligula of the seventh white 
in color and submembranous, subcylindric, slender, with the apex 
slightly expanded and truncate; female having the sixth ventral 
obtusely and evenly rounded at tip. Length 2.8 mm.; width 0.5 mm. 
Mississippi (Vicksburg) and Louisiana (Bayou Sara). 
ludovicianus nu. sp. 
The sexual characters are somewhat obscured in the only 
male at hand by a hardened exudation filling the emargination 
of the sixth ventral, so that I am not certain of the entire 
correctness of the description; the white submembranous 
ligula, however, is clearly defined and is radically different 
from anything else in the Paederini that I have observed. 
Leptogenius Csy. 
This genus is also represented by a single species thus far, 
readily distinguishable from the preceding by its still smaller 
size and more slender form, small eyes which are setulose and 
not nude, oblong, and not orbicular, basally sinuato-truncate 
head and normal terminal segments of the abdomen; it may 
be briefly described as follows: — 
Body minute, slender, subparallel, only feebly convex, densely dull in lustre 
and closely, somewhat coarsely and rugosely punctulate, pale red- 
brown in color, the elytra generally darker except toward the sides and 
base; head well developed, longer than wide, parallel at the sides, the 
angles rounded, the eyes rather coarsely faceted and at between two 
and three times their own length from the base, slightly convex and 
prominent; antennae not quite as long as the head; prothorax small 
though fully three-fourths as wide as the head, about as long as wide, 
the sides subangulate and narrowly rounded at apical fourth, the base 
