Casey — A Revision 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 6.6 i esdsaceccon sece ee havewewsbdameeracd vseclccetcceccos 8 
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 beneathin both sexes; integuments 
shining, simply and rather coarsely punctate, the neck one-half as wide 
as the head; male ventral characters very slight. Sonoran..Neomedon 
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; eyesrathersmall; palpinormal; antennae 
rather thick, filiform, the third joint only slightly longer than the sec- 
ond; prosternum acute'y 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, SOMOTAN «es sseseercereeccccsescee seseseee sees POlymedon 
3 — Labrum bidentate... .sesseceesececcsccscvcsessccsesseccccesscesece 4 
LAOramM GQuadridentate.. oc. cccccssrcesccscccsncs ccs ccs renesecesesseceeld 
Labrum without teeth, though having the usual small median notch......18 
4— Antennae 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 
ClOSES TNS SCUIPLUTE $s ccsccincsccc. Seslncec cdccnscvesedeccescceccsseses) & 
Antennae normal, equally or subequally thick throughout, sometimes feebly 
enlarged COWS tIP.. «66 ciccec seociccecdavnceeseds cops ssedvévevuavevse G 
5 — Gular sutures moderately separated, gradually converging and most nar- 
rowly separated toward base; eyes 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 length, the anterior more or less 
distiuctly dilated; species very numerous, small in size, alwaysrather 
distinctly punctured, the male sexual characters simple, the fifth seg- 
ment scarcely modified. South America to the warmer parts of North 
AMETICA oo cc recessec cece recs ccccecccee recesses secs sess sees SCLOCHSFIS 
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 
