junei8j9-] Casey: On American Coccinellid^. 161 



is in no way related, but belongs to the Scymnillini, where it forms 

 the type of a new and rather isolated genus. The color of the body 

 is uniform and black or piceous. 



Black, the elytra sparsely punctured. Maryland and South Carolina. 



zimmermanni Crotch 



Brownish or piceous ; elytra more coarsely and quite closely punctured. Southern 



California and Arizona. occidental is Horn 



These species are of an oblong-oval form and 1.5-2.0 mm. in 

 length. They may be recognized at once by the very large head and 

 deeply emarginate prothorax, the sides of which are discontinuous with 

 those of the elytra. 



Rhyzobiini. 



The insects of this tribe are of a regularly oval, moderately convex 

 form and are clothed throughout with more or less fine semi-erect 

 pubescence, as in Scymnini. They are not, however, closely allied to 

 that tribe, as they possess wider, moderately descending and internally 

 margined epipleurae, long and slender antennae, with loosely connected 

 serrate 3-jointed club, entire or subentire and coarsely faceted eyes and 

 entire metacoxal plates, always shorter than the segment, and, in the 

 two genera defined below, the presternum is flat, moderately or widely 

 separating the coxae and with two strong entire converging carinae. 

 The abdomen has six segments, the sixth very small, the maxillary 

 'palpi normally securiform and the legs perfectly free. The prothorax 

 is very feebly and evenly sinuate at apex, with broadly rounded angles 

 as in Psylloborini. The tarsal claws are well developed, evenly arcuate 

 and slender, with a moderate subquadrate dilatation internally at base, 

 but in the males the anterior and intermediate are thick and bifid, thus 

 forming an exception to the entire family as far as known. The genera 

 before me may be defined as follows : — 



Epistoma transversely truncate and simple at apex ; hypomera nearly simple ; proster- 

 nal carince arcuate, diverging widely at base, coalescent at apex ; metacoxal plates 

 very short *Rhyzobius 



Epistoma deeply emarginate, the bottom of the sinus transverse and having a mem- 

 branous margin ; hypomera with a narrow deep groove extending, parallel to the 

 side margin, from the apex nearly to the middle, the prosternal carina; straight, 

 not coalescent at apex ; metacoxal plates much larger, extending almost to the 

 apex of the segment Lindor us 



The definition of Rhyzobius, — the original spelling of which I 

 agree with Wollaston in following, — is taken from the South African 

 irimeni Csy. 



