Casey — A Bevision of the American Paederini. 151 



Gular sutures always separated, sometimes very feebly impressed and occa- 

 sionally altogether effaced and traceable only by differences in sculpture 

 between the intersutural region and the remainder of the under surface 



of the head 3 



2 — Labrum short and very broad, truncate, broadly, feebly sinuate at the 

 middle and having six very small teeth or tooth -like undulations; 

 species very large in size for the present group ; paraglossae coarsely and 

 angularly bilobed ; palpi normal, the third joint of the maxillary fully a 

 third longer than the second; eyes moderate; antennae rather thick, 

 filiform, the third joint very much longer than the second ; prosternum 

 feebly and obtusely carinate posteriorly; tarsi moderately slender, the 

 basal joint of the posterior distinctly longer than the second, the an- 

 terior distinctly dilated and spongy beneath in both sexes; integuments 

 fihining, simply and rather coarsely punctate, the neck one-half as wide 

 as the head; male ventral characters very slight. Sonoran..Neomedoil 

 Labrum narrower, more rounded, with four acute and well developed teeth 

 and a small median notch, which is acutely denticulate at the bottom; 

 species moderate in size; paraglossae of the usual form, acutely 

 bilobed; ligula setose at tip; eyes rather small ; palpi normal; antennae 

 rather thick, filiform, the third joint only slightly longer than the sec- 

 ond; prosternum acutely carinate posteriorly; tarsi rather short and 

 thick, the basal joint of the posterior much longer than the second, the 

 anterior thickened but scarcely dilated ; integuments very densely dull, 

 the sculpture rather coarse and extremely dense; neck rather narrow, 

 from rather more than a third to two-fifths as wide as the head; male 



unknown. Sonoran Polymedoil 



3. — Labrum bidentate 4 



Labrum quadridentate 13 



Labrum without teeth, though having the usual small median notch 18 



4 — Autennae with the two basal joints normally thick, the remainder very 



slender, filiform and verticillate; labral teeth small but distinct and 

 approximate, the notch small; species generally dull in luster, with 



close fine sculpture 5 



Antennae normal, equally or subequally thick throughout, sometimes feebly 

 enlarged toward tip , . 6 



5 — Gular sutures moderately separated, gradually converging and most nar- 



rowly separated toward base; tyes more or less well developed, the 

 neck rather broad but usually less than half as wide as the head; pro- 

 sternum not carinate except posteriorly ; tarsi moderately short and 

 somewhat thick, the basal joint of the posterior distinctly longer than 

 the second, two to four decreasing in lergth, the anterior more or less 

 distinctly dilated; species very numerous, small in size, always rather 

 distinctly punctured, the male sexual characters simple, the fifth seg- 

 ment scarcely modified. South America to the warmer parts of North 



America ^ciocharis 



Gular sutures very widely separated and most approximate anteriorly, 

 thence widely diverging to the base of the head; eyes rather small; 

 neck nearly half as wide as the head; prosternum not at all carinate; 

 tarsi short and moderately thick, the first joint of the posterior dis- 

 tinctly longer than the second, two to four equal and about as long as 



