Casey — A Revision of the American Paederini. 57 



thorax, oblong, the neck very wide, four-fifths as wide as the 

 head ; labrum very short, transversely truncate, with a very small 

 rounded median sinus, at each side of which there is a small and 

 abruptly formed tooth; antennae short, rather slender; gular sutures 

 evenly arcuate, moderately separated, most approximate at the middle; 

 maxillary palpi with the third joint much longer than the second, 

 strongly obconical and compressed; prothorax oblong, the angles 

 distinct; prosternura more developed before the coxae than in the 

 preceding genus; elytra well developed, as long as the prothorax or 

 longer, the basal angles distinct; hind wings probably well developed; 

 abdominal segments not impressed at base; legs slender, the hind tarsi 

 filiform, the joints proportioned nearly as in the preceding; anterior 



tarsi, rather feebly dilated . Europe *Leptobiuin 



3 — Body very small in size, slender, parallel, convex, polished, distinctly, 

 evenly and more closely punctured, the abdomen relatively finely, very 

 sparsely punctulate; pubescence entirely inconspicuous; head about 

 as wide as the prothorax, somewhat pyriform ; labrum as in Leptobium, 

 bidentate, the teeth longer and more aciculate; gular sutures well 

 separated, converging to about the middle, thence subparallel to the 

 base; maxillary palpi with the third joint much longer than the second, 

 subcylindric, rapidly narrowed at base, sparsely setulose; antennae 

 short, one-half longer than the head, slender basally, rapidly incrassate 

 distally; neck narrower, three-fifths as wide as the head; prothorax 

 suboval, widest anteriorly, with a narrow median smooth liue; prester- 

 num well developed before the coxae; elytra extremely short as in 

 Dolicaon, with rounded basal angles, the hind wings undoubtedly 

 obsolete or vestigial; abdominal segments not impressed basally, 

 legs slender, the hind tarsi nearly as in Leptobium, the anterior feebly 

 dilated. Europe *Scetoiiomus 



Dolicaon Lap., is founded upon the comparatively gigantic 

 lathrohioideH Lap., of the regions about Cape Town. Among 

 some 450 species of Coleoptera which I took in that vicinity, 

 there was only this one Paederid, — the largest species of the 

 tribe known to me, — as though the entire paederoid energy 

 of the country had been concentrated in this single species. 

 The diagnosis of Leptobium (n. gen.) given above, is taken 

 from the biguttulum, of Lacordaire, and that of Scotonomus 

 Fauv., from the ro.ymondi, of Fauvel. The species, although 

 very few in number, display in Dolicaon and Scotonomus the 

 greatest disparity in size observable within any of the sub- 

 tribes of Paederini. In the formation of the very short 

 elytra and probable absence of hind wings, these two genera 

 are identical and wholly different from Leptobium, the 

 European species requiring a new generic name, since both 



