The Hymenoptera of the Georgetown Museum. 215 
widened to the apex from the base. There is an indistinct furrow down the 
middle of the scutellum. 
Tts ventral black markings vary in size and shape ; they vary also in colour 
varying from black to fuscous. 
Polybia sulciscutis, sp. un. 
Black with a tendency to fuscous, the face except for a small conical spot 
in the centre, the clypeus except for a small triangular spot in the centre above 
the inner orbits from opposite the lower ocellus, to the face, narrow above, 
broad below, the mark filling the eye incision, a line running down from the 
ocelli to near the antennez, the end obliquely narrowed to an acute point, a 
spot between the antenne, the outer orbits entirely, the malar space, mandi- 
bles, except the teeth, which are brown, 2 lines down the mesonotum, the 
scutellar keels the base and apex of scutellum, the base more widely than the 
apex, basal half of post-scutellum, the base of the black apical part irregular, 
the metanotum except the central furrow, the line on which becomes widened 
towards the apex, the propleuree except fora mark twice longer than wide, 
narrowed below, where it is transverse, the meso and metapleure except for a 
fuscous line on the former along the furrow, the sternum, the sides of the Ist 
abdominal segment narrowly on the basal half, the basal fourth of the 2nd, the 
base of the black part irregular, narrower lines on the 2nd to 4th on the apex, 
continued backwards on the sides to the base, a narrower, more obscure line 
on the 5th, the whole of the 6th and the ventral segments, pallid yellow, almost 
white. Legs of the same pallid yellow colour as the body, a fuscous line on 
the apical half of the fore femora behind, a spot on the upper basal part of the 
middle, almost the basal half of the middle the tibie behind, a line on the 
middle coxe behind and a short and a longer one on the hinder, fuscous. 
Antennal scape pale yellow, its apex fuscous, the flagellum reddish brown, 
its basal 6 joints black above. Wings clear hyaline, the nervures blac k, the 
stigma fuscous, the basal abscissa of tadius as long as the following 2 united ; 
the 2nd as long as the space bounded by the recurrent nervures. Scutellum 
with a wide furrow, with obliquely sloped sides down the centre, the apex of 
post-scutellum narrowed to a broad, bluntly rounded point. Abdominal 
petiole longish triangular, becoming gradually widened from the base to the 
apex, slightly longer than the 2nd segment which is broader than it is wide at 
the apex. The ventral surface is entirely yellow. Female. Length 6 m.m. 
Polybia occidentalis, Oliv.—pygmaa F. 
A species very variable in colouration and size, varyin gfrom being almost 
entirely black, to having the body, and especially the thorax, largely marked 
with yellow, e.g. the metanotum may have only 2 small spots, 2 large oval 
ones, or may be entirely black. Cf. Fox, Proc. Acad. Nat. Sc. Phil., 1898, 
449; Schulz, Sitz. d. mathem.—phys. Klasse. d. Bayer. Akad. d. Wissen ; 
XXXII, 797 ; Hymen. stud. 127; Ducke, Boletim do Musen Goeldi, IV, 349. 
The workers vary considerably in size. The markings run from white to 
orange yellow. 
