Casey — A Revision of the American Paederini. 219 
Labrum broadly rounded or subtruncate at apex, the teeth two in number, 
more or less aciculate and always approximate; second joint of the 
maxillary palpi much shorter than the third; anterior tarsi finely, 
densely pubescent beneath; prosternum very finely, feebly carinate 
CHTOUGHONE. ccccccsccccsccccsecce voce cccvesvverescsncecsescsscencce Z 
Labrum broadly sinuato-emarginate at apex, the emargination having two 
short obtuse and more widely separated teeth; second palpal joint very 
much shorter than the third; anterior tarsi not at all dilated, having 
long coarse hairs beneath; prosternum finely, unevenly and feebly 
CHPIAGE 6 vines kU chsh eKS 0d sinh b vaek badd eb be cahsb Medes bt Melweke au ted~ oo 
Labrum quadridentate at apex and generally broadly subtruncate and 
triemargimate, .....cccersccrcccceccccccevccscse cscs sesescssseccseen & 
2— Head rounded to subtruncate at base, the body rather slender; legs and 
tarsi slender; sculpture more or less coarse. Palaearctic and Nearctic 
TOZIONS. sc cnsscviesecccscnesise cove cdcccstessescesencce secs eves PH CUs 
Head broadly sinuate at base, the body very stout; legs and tarsi thick; 
sculpture very fine and dense. Nearctic regions.........Pachystilicus 
3 — Body very stout with the head orbicular; third maxillary palpal joint 
unusually small, subcylindric and bent; sculpture fine and dense, the 
vestiture very short and stiff; femora and tibiae rather thick, the hind 
tarsi slender and almost as long as the tibiae. Myrmecophilous. 
Nearctic regions... cose cscocccccccsccccccesece coceces cece MOPAStILICUS 
4 — Outer pair of labral teeth as large and conspicuous as the inner; second 
palpal joint much shorter than the third; anterior tarsi slightly dilated 
and more densely pubescent beneath; legs slender; sculpture coarse as 
in Stilicus. Palaearctic regions. .....scesececseccerceese  StiLiCOSOMA 
Outer pair of labral teeth very minute; anterior tarsi not dilated and 
usually not densely clothed beneath; sculpture of the integuments 
RIWAYS VOFY TNC ANI GONBG s o4 sis sre ses sos Cle hice lis dloseccesece & 
5 — Prosternum strongly carinate throughout its length.........seeesees 6 
Prosternum not at all carinate except posteriorly near the coxae......... 7 
6 — Inner pair of labral teeth short and broad, widely separated, each tooth 
deeply bifid and forming two acute denticles; labrum not at all pro- 
duced in the middle but broadly subtruncate; head rounded at base, 
the eyes moderate or rather small; second palpal joint but little shorter 
than the third, moderately elongate; gular sutures as usual; prothorax 
oblong-parallel, the angles distinct. Nearctic regions......Stilicolina 
Inner pair of labral teeth strong, the labrum elongated in the middle; 
maxillary palpi very long; mandibles broad; prosternum elongate, the 
prothorax without the lateral angles of Stilicus. Tropical America. 
*Eustilicus 
7 — Labrum broadly truncate and deeply trisinuate, the median teeth long, 
simple and aciculate; mandibles broad and strong; maxillary palpi 
long, the second joint slightly shorter than the third; gular sutures 
meeting behind the middle; head subtruncate at base, the eyes very 
small; prothorax obtrapezoidal, the anteriar angles rounded; legs long, 
the femora somewhat stout. Sonoran region.......... ----Qmostilicus 
The characters of the Mexican and Central American 
Eustilicus Shp., are taken from the ‘*‘ Biologia; ’’ at first it 
