218 Trans. Acad. Sct. of St. Louis. 
one-half wider and a fourth longer than the prothorax and very much 
wider than the head, broadly convex, impressed on the suture toward 
base; abdomen toward base much narrower than the elytra but rapidly 
broadening, so that the apex of the fourth segment is somewhat wider 
than the elytra, the fifth segment obtrapezoidal and nearly as long as 
the two preceding combined; legs slender. Male with the fifth ventral 
unmodified, the sixth having a triangular incisure at apex about one- 
half deeper than wide, the surface feebly impressed in prolongation 
thereof. Length 3.2 mm.; width 0.55mm. Texas (Houston and Lu-~ 
LING) cseceve seve vccwcceceste sees veveceseesstoucscesoecesse MittGh LMC, 
Form, sculpture and coloration almost. completely similar to nitida, the dark 
subapical cloud of the abdomen usually confined to the discal parts of 
the fifth segment only and the general color rather paler than in nitida; 
head nearly similar but with much less broadly rounded basal angles, 
the truncate part of the base wider and more transverse; prothorax 
nearly similar, the elytra larger and relatively more elongate, the ab- 
domen notably broader and less dilated posteriorly, the fifth segment 
much shorter than the two preceding. Male with the fifth ventral un- 
modified, the sixth having a moderately large notch at apex, the emargin- 
ation triangular with straight sides and angulate apex and nearly twice 
as wide as deep, the adjacent surface not at all impressed. Length 3.1 
mm.; width 0.6mm. California (Yuma and the Needles) .sonorica n. sp. 
These species are both rather abundant and somewhat re- 
semble certain ants in their movements and coloration. Nitida 
was originally described under the generic name Hchiaster. 
STILICI. 
The few generic types of this well-marked subtribe are 
remarkably consistent in the form of the tarsi, neck and 
gular sutures and differ among themselves principally in 
modifications of the labrum, maxillary palpi, prosternum and 
sculpture of the integuments. ‘The hind tarsi are more or 
less elongate throughout, with the basal joint always distinctly 
longer than the second and sometimes as long as the next two 
combined but varies considerably in relative elongation, even 
within the limits of Stilicus itself. The neck is always very 
slender and not variable in width, as it is in the Scopaei, and 
the gular sutures are invariably coalescent and unified at least 
toward base. The anterior tarsi are generally very slightly 
dilated and spongy-pubescent beneath. The genera known 
to me may be briefly described as follows : — 
