Casey — A Revision of the American Paederini. 147 
Weise as a subgenus of Medon. They differ radically from 
the Medones, however, in the structure of the prosternum 
under the coxae, this sclerite ending posteriorly in an acute free 
point, coming far from attaining the mesosternum and formed 
as in the Lathrobia. The labrum, also, differs from anything 
known in the Medones and in fact is subtribally distinctive, 
for, although in several other subtribes, such as the Paederi 
and Medones, we occasionally observe a short sharp denticle 
at the bottom of the median emargination, there is no other 
group in which the median tooth becomes the most conspicu- 
ous feature or formed as it is here. In short, the distinctive 
character of the labrum in the Lithochares is a median tooth, 
without trace of lateral denticulation, while in the Medones 
it is the development of lateral teeth and absence of anything 
but a rarely observable and wholly different medial denticle, 
The Lithochares agree with the Medones, however, in having 
the anterior tarsi either dilated or undilated, departing from 
the uniformly dilated condition of the Lathrobia. We have 
but two genera as follows :— , 
Form rather stout, parallel, larger in size, moderately convex, finely, 
densely sculptured and dull in lustre; head oblong, well developed, 
broadly sinuato-truncate at base; eyes moderately large, not very 
prominent; labrum well developed, broadly arcuato-truncate, with a 
short, obtuse and dorsally swollen median tooth, not projecting be- 
yond the general line of the apex and bordered at each side by a small 
emargination; gular sutures well separated anteriorly, gradually con- 
verging and most approximate and narrowly separated at the base; 
ligula densely fimbriate at tip with broad obtuse strigose and sub- 
membranous spicules; paraglossae compressed; labial palpi slender 
and elongate; maxillary palpi slender, elongate, the third joint elongate- 
oval, with the apical cavity small, the fourth joint very slender and 
aciculate, not very oblique; antennae slender, filiform, moderate in 
length, the joints obconical; neck barely two-fifths as wide as the 
head; prothorax obtrapezoidal, broadly produced in the middle at apex, 
truncate at the neck; prosternum short before the coxae; elytra well 
developed, longer and wider than the prothorax; abdomen with the 
segments only feebly impressed at base; legs slender, the anterior tarsi 
moderately dilated, densely padded beneath, the posterior three-fourths 
as long as the tibiae, with the first joint much longer than the second 
and subequal to the fifth, nearly as in Dolicaon. America.. Aderocharig 
Form rather more slender, less parallel, the head small, finely, densely dul] 
in sculpture throughout; head broadly arcuato-truncate at base, the 
eyes large and conspicuous; labrum as in Aderocharis but with the 
