20 Trans. Acad. Sci. of St. Louis. 



3 — Neck more or less broad; fourth palpal joint distinct, more or less 

 conical Cryptobia 



Neck extremely slender as in Scopaeus; fourth palpal joint indistinct, ap- 

 parently obtuse and more or less pubescent *Sphaeroiiia 



4 Ligula bilobed at tip; sculpture and vestiture never very dense; labrum 



never strongly dentate at the middle , 5 



Ligula densely fimbriate at tip ; labrum dentate only at the middle ; sculpture 

 and vestiture very dense, the surface devoid of lustre 8 



5 — Fourth joint of the maxillary palpi compressed and lineate at apex and 



clothed with fine pubescence 6 



Fourth palpal joint conical, sometimes aciculate, always nude 7 



6 — Neck very broad; body feebly convex; hind tarsi filiform... *Dolicaones 

 Neck narrow; body strongly convex; tarsi with the fourth joint lobed be- 

 neath Paederi 



7 — Anterior tarsi always strongly dilated in both sexes, the posterior fili- 



form and simple ; body more or less parallel as In Dolicaones and mod- 

 erately convex as a rule Latlirobia 



8 — Body more or less parallel and feebly convex; anterior tarsi vari- 

 able Lithochares 



9 — Ligula loosely fimbriate at tip ; neck never very slender Medones 



Ligula tricuspid at tip; neck variable but never very broad Scopaei 



10 — Prosternum remaining far below — viewed from below — the level of 



the edges of the hypomera, with a widely open space between the two 

 surfaces; tarsi filiform, the fourth joint simple; antennae as in Paederi; 

 neck very slender Stilici 



Prosternum approaching very close to the edge of the hypomera in a verti- 

 cal sense, the opening between them narrow but evident; tarsi short 

 and stout, the fourth joint bilobed; antennae straight, not flexile at 

 the first joint, the apex of the latter not sinuate behind; neck very 

 slender Stilicopses 



Prosternum touching or connate with the edges of the hypomera, the coxal 

 cavities entirely chitinous 11 



11 — Fourth tarsal joint bilobed; antennae straight, not flexile at the first 



joint, the apex of which is not sinuate behind; mentum simple; max- 

 illary palpi slender, the third joint elongate and fusiform, the fourth 

 small, obtuse and inconspicuous; neck moderately narrow; integuments 



moderately dense ; species small in size Sunii 



Fourth tarsal joint simple; antennae flexile, the apex of the flrst joint 

 sinuate posteriorly; mentum usually modified at the sides, sometimes 

 spinose; third joint of the maxillary palpi more or less securiform or 

 otherwise abnormal, the fourth very minute and indistinct; neck usually 

 very slender; integuments thicker and much denser; species generally 

 very small in size Echiasteres 



In the following pages 89 genera are defined in the tables 

 of genera, of which 64 occur within the limits of the United 

 States of America and 25 are exclusively foreign; these 

 latter are distinguished in each case by a prefixed asterisk. 



