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 uudilated, 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 apes 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 ar.d 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 obtrapczoidal, 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 blender, 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.. Aderocharis 



Form rather more slender, less parallel, the head small, finely, densely dull 

 in sculpture throughout; head broadly arcuato-truncate at base, the 

 eyes large and conspicuous, labrum as in Aderocharis but with the 



