190 
ventral plate, as shown in Figures 34 to 39, Plate XVIII. The form of 
this plate in impictiventris, euschistoides, ictericus, and servus is almost 
identical, the central emargination being almost evenly rounded off later- 
ally. In addition to this character all of the species of this group have a 
distinct central notch in the thin plate which projects from the caudal 
margin of the upper plate of the hypopygium, the notch varying slightly 
in depth in the different species (Fig. 37). The two species tristigmus 
and pyrrhocerus have the hypopygia of slightly different form, the ventral 
plate having a slight but distinct angle at each side of the central emargi- 
nation, and the thin plate above referred to sharply produced in center, 
not notched (Fig. 35). Other forms of the hypopygial structures are 
shown in Figures 34, 36, 38, and 39. 
Kery To SPECIES 
A distinct black dot in each anterior angle of the ventral segments.7 
[Juga with a few sparse punctures along the lateral margins and between 
ocelli; disc of pronotum and elytra largely impunctate; antennae péle...... 
BRO OI REU AT ree rr os. AS CORIACEOUS er rnin cine ord Bier & co oi one subimpunctatus.] 
Juga above densely punctate; in side view obliquely truncate, not exceeding 
the obtuse median anterior profile formed by the tylus and labrum; mar- 
gin of male genital segment, as viewed from behind, with distinctly . 
limited median notch; antennae usually pale or reddish; 9 or 10 mm. 
Side margin of pronotum nearly straight to the obtuse lateral angles, an 
evident pale edge, sharply contrasting above with a well-defined dark 
border; head above with dark margin; no median ventral spots; notch 
in male genital segment V-shaped, a similar, very small incision each 
SIMSCOE Tio atrovent neneker esac Retcts, offcte io f<taeciee cated chee kek Coenen a eRe are ae politus. 
Side margin of pronotum deeply sinuate, pale edge narrow, dark border 
shading off very gradually inwards, none on head; venter in front of 
genital segment with one or more median spots, rarely none; last tarsal 
usually black-tipped; notch in male genital segment semicircular, 
limited each side by a small tooth. 
Lateral pronotal angles rounded or subacute; ventral spots 2-4; darker, 
antennae often black apically; imagines common before and after July.. 
SS Nena rere Met Pe Hoc cata, of in eR PEN Oe PhORN hos icy Sis MS See dads tristigmus. 
Lateral angles spinose or acute; ventral spots 0-2; paler, antennae pale; 
common southward, especially during July................ pyrrhocerus. 
Juga above rather sparsely punctate along the middle of the disc; margin of 
male genital segment, viewed from behind, broadly concave without defi- 
nitely limited notch; antennae pale or apically black; length abut 12 or 
13 mm. 
Juga in side view acutely projecting more or less beyond the median pro- 
file, as seen from above usually exceeding tylus; male genital segment 
without black spot; width across elytra 7-8 mm. 
7 Turn apex of abdomen to the light to avoid shadows at the anterior angles. 
