224 Trans. Acad. Sci. of St. Louis. 



only two genera that do occur there, the subcoxal plates are 

 incomplete as well as imperfectly chitinized. 



The Falagriae are very small beetles as a rule, of slender 

 and graceful form, with much narrower neck than in the 

 Tachyusae, long and generally slender legs with filiform tarsi, 

 the posterior usually having a greatly elongate basal joint, 

 and the pronotum is always narrowly and acutely impressed 

 along the median line, sometimes broadly, deeply and con- 

 spicuously but in other genera very feebly or obsoletely. The 

 singular sexual differences in the pronotal impression, and 

 sometimes in sculpture as well, prevailing in some of the 

 genera of the Tachyusae, are apparently not observable in 

 the Falagriae, but there are some analogous though very 

 feeble characters at the apex of the sixth ventral plate, so 

 slight however that they will not be noticed in the descrip- 

 tions of the species except in certain instances. The first 

 three tergites are rectilinearly impressed at base, but there is 

 never a trace of the carina so developed in Tachyusa, and the 

 abdomen is always rather wide, parallel and never narrowed 

 toward base as it is in some of the genera of the preceding 

 subtribe; the elytra, also, are never more than very feebly 

 produced or subangulate at the sides of the apex. The genera 

 tLay be defined as follows : — 



Flanks of the pronotum broadly convex and strongly inflexed, narrowing the 

 prosternum, the hypomera not delimited from the flanks; middle aceta- 

 bula more or less well defined throughout by a beaded edge ; proster- 

 num wholly corneous under the coxae 2 



Flanks feebly inflexed, the prosternum normally broad, the hypomera de- 

 limited at the sides, usually but not always by a beaded edge ; middle 

 acetabula always widely open behind, never having a trace of beaded 

 edge ; mesosternum never carinate 3 



2 — Middle acetabula well separated, surrounded throughout by a flne strong 

 beaded edge, deep, with abruptly steep walls throughout, the meso- 

 sternum elevated in median third, more strongly anteriorly, the surface 

 perfectly flat and without trace of carina, the process very short, not 

 extending much beyond anterior fourth of the acetabula, squarely trun- 

 cate at tip, the latter not in the least free but joined to the longer and 

 equally wide, flat and transversely truncate tip of the metasternal pro- 

 jection by a short flat isthmus on the same level as the apices ; pro- 

 sternum before the coxae defined externally and internally by similar 

 posteriorly cusped beaded edges; neck nearly a third as wide as the 

 head, the latter arcuato«truncate at base with evident angles, the eyes 



