POTAMOBATES., 155 
1. Potamobates unidentatus, n.sp. (Tab. IX. figg. 20, apterous ¢ ; 20a, ditto, 
from beneath; 20 4, ditto, first genital segment; 20, ditto, second genital segment, 
from the side, opened, to show the angular dilatation of one side; 21, winged 2.) 
Winged form. Broad, moderately elongate, black; the head with a posteriorly widened median vitta between 
the eyes and the sides in front, the pronotum with a broad triangular patch at the base of the anterior 
lobe and the sides and hind margin of the posterior lobe, an elongate mark on the metanotum, the 
connexival margins, the body beneath, the lower part of the pleura (a short streak in front of the inter- 
mediate coxse excepted), the coxee and trochanters, and the basal half of the rostrum, ochraceous or 
flavous; the legs blackish, with the anterior femora above and in front to near the apex and at the base 
beneath, the posterior femora at the base beneath, the intermediate tibia towards the apex, and the 
intermediate tarsi, obscure testaceous, the anterior femora paler at the base ; the elytra and wings brown, 
the elytra paler along the costa; the head, the pro-, meso-, and metanotum, and the abdomen, shining, 
the pleura and under surface opaque; above and beneath finely pubescent, the mesopleura with a narrow 
longitudinal stripe and two triangular patches behind, the pro- and metapleura each with a triangular 
patch, the sides of the metanotum behind, and the outer margins of the dorsal segments of the abdomen, 
golden-pubescent, the pubescence of the under surface paler than the ground-colour; the base of the 
anterior femora with a few long bristly hairs in front and behind. Antenne with joint 1 nearly or quite 
as long as 2-4 united, 2 and 3 subequal in length, each shorter than 4. Pronotum obsoletely carinate 
down the middle of the posterior lobe. Propleura extending outwards to about as far as the eyes. 
Mesopleura very broad throughout, extending laterally to far beyond the posterior lobe of the pronotum, 
gradually widening to the intermediate coxe. LElytra extending to considerably beyond the abdomen, 
the wings about one-third shorter. Abdomen with an oblong smooth spot on the middle of each of the 
dorsal segments. 
Apiterous form. Pronotum short, transverse. Mesonotum flattened and shining, with a median vitta, and a 
small triangular spot on the disc on each side of it a little beyond the middle, and sometimes a line 
extending from the spots downwards, ochraceous. 
g. Terminal ventral segment abruptly transversely depressed. beyond the middle, the apex deeply arcuate- 
emarginate in the centre, the apical margin ciliate; first genital ventral segment obliquely sulcate, with 
the apical margin produced into a prominent pointed tooth on the right side only; second genital segment. 
broadly and angularly dilated on the right side near the base; sixth connexival segment a little produced 
at the outer apical angle, the apex obtuse. 
©. Sixth connexival segment more pointed at the outer apical angle. 
Length 8-83, to end of the elytra 10, breadth 23-23 millim. 
Hab. Panama, Bugaba (Champion). 
One winged female and numerous apterous specimens of both sexes have been 
obtained of this species. The asymmetrical armature of the two genital segments of 
the male is quite constant. The anterior femora sometimes have the base ‘only 
testaceous. The mesothorax in the apterous form is about two and one-half times 
the length of the prothorax; it is shaped somewhat as in Platygerris, but the meso- 
pleura are narrowed forwards. 
2. Potamobates bidentatus, n. sp. (Tab. IX. figg. 22, 3 ; 22 a, ditto, genital 
segments, from beneath.) 
Apterous form. 3. Broad, elongate, black; the head with a short stripe between the eyes, the pronotum with 
a narrow median line on the anterior lobe, the coxee, the under surface (a small spot on each side of the 
mesosternum beyond the middle excepted), and the base and underside of the anterior femora, ochraceous, 
the intermediate tibie and tarsi obscure ferruginous; the upper surface, the pleura excepted, somewhat 
shining; above and beneath finely pubescent, the lower part of the propleura, a longitudinal stripe on the 
mesopleura, two triangular patches on the latter behind and one on the metapleura, and the sides of 
20* 
