1967] 
Darlington — Carabidae 
317 
pressions of pronotum, margins and apices of elytra, and much of 
lower surface with more or less distinct, close, nearly isodiametric 
microsculpture. Head large; clypeal suture impressed; lateral ridges 
rather thick, becoming obsolete posteriorly above or just back of pos- 
terior edges of eyes, rounded anteriorly, not distinctly interrupted at 
the bend but obliquely grooved externally; neck constriction im- 
pressed; surface of head unevenly punctate, almost impunctate on 
middle of front and behind neck constriction; antennae with first 
segment moderately, not suddenly clavate; supra-maxillary plates 
dilated laterally, angulately rounded ; mandibles of both sexes ex- 
panded and margined externally near base, those of male broadly, 
irregularly impressed and wrinkled above near base, the left one with 
a strong tubercle on inner side of upper surface. Prothorax : pronotum 
with fine median line and deeper, uninterrupted lateral sulci ; surface 
of pronotum punctate across base and apex and near lateral margins, 
and much more sparsely so on disk. Elytra each with a distinct, 
short plica above the humerus, directed backward and outward ; 
elytral surface rather finely punctate, the punctures sparse on the 
disk. Inner wings fully developed. Stridulating files, under lateral 
margins of prothorax, present in both sexes. Male with mandibles 
modified as described above; copulatory organs as figured (Fig. 4). 
Length: 19- 19.5 mm. 
Rejnarks. Twenty-seven previously described species of Siagona 
are recognized from the Oriental Region. Most of them are included 
in Andrewes’ (1929, pp. 178-181), “British India” key, and 18 of 
them are represented in the Museum of Comparative Zoology, al- 
though not all by males. Nevertheless I have had difficulty in placing 
the present new species satisfactorily. 
The most striking characteristic of the new species is the tubercle 
of the left mandible of the male. Carinae or tubercles are variously 
developed on the upper surface of the mandibles inwardly near the 
base, in males only, in different Oriental Siagona. Many of the 
species lack them. The males of obscuripes Chaudoir, strata Dejean, 
and baconi Chaudoir have a longitudinal carina about equally de- 
veloped on each mandible, the carinae being respectively weak, mod- 
erate, and strong in the three species named. The male of induta 
Chaudoir is said to have an elevated boss on each mandible, that on 
the left higher than that on the right. The male of crassidens Bates 
is said to have only the left mandible tuberculate. The males of 
angulifrons Bates and rustica Andrewes are said to have the right 
mandible carinate, the left one only vaguely or not so. Andrewes 
