The Hymenoptera of the Georgetown Museum. 211 
mesopleure, bui the top from the tubercles is raised, this part being roundly 
narrowed below, but not into a semi-circle. Abdominal petiole not quite so 
long as the scutellums and metanotum united and shorter than the 2nd and 
3rd segments united ; the apex becomes gradually narrowed, but not much, 
from the spiracles, not forming a distinct node. The 2nd segment is longer 
than the following segments united ; it is about one quarter longer than wide. 
Has the size, shape and general colouration of P. chrysothorax, Saus. and 
P. sericea, Ol., from both of which it may be known by the uniformly fuscous 
violaceous wings, by the thorax wanting black and by the abdominal petiole 
not being nodose at the apex. It shows an approach to Megacanthopus ; the 
tarsal joints at the apex are not equally lobate. 
Polybia lilacea ¥. 
Polybia dimidiata, ¥. 
Polybia «injucunda, Saus. 
Polybia bimarginata, sp. n. 
Black, densely covered with a white pile, the dilated apical part of the 
petiole from the spiracles and the rest of the abdomen rufo-testaceous, a short 
narrow line on the inner orbits, opposite the antenne, a line round the pro- 
notum above, a slightly broader line on the base of the post-scutellum, and a 
conical line of variable size on either side of the apical half of the metanotum, 
pale yellow ; the knees testaceous, the spurs of a whiter testaceous colour ; 
wings hyaline, the costal cellule fulvous, deeper in tint at the apex, the radia] 
cellule and the apical cubital ight smoky ; the basal nervures testaceous, the 
apical black. Female. Length 8-9 mm. 
Covered all over with a short white pile, the face and clypeus densely 
covered with moderately long black hair. Clypeus as broad as long, its 
apex broadly rounded, smooth and shining. Ocelli in an equilateral triangle, 
the hinder separated from each other by the same distance as they are from 
the eyes. Base of thorax transverse, margined, angled laterally. Metanotum 
with a distinct furrow, commencing near the base, continued to the apex and 
becoming gradually widened. Abdominal petiole a litile longer than the 
post-scutellum and metanotum united, narrow, slender to the spiracles, then 
becoming dilated, but not much ; then becoming widened into a longish oval. 
The 4 or 5 apical joints of the antenne are rufous below. 
Comes near to P. injucunda, Saus. 
. Polybia phthisica, ¥..sec., Sauss. 
The above species is probably represented by 3 female and 2 male exam- 
ples. P. cayennensis, F.,is no doubt the same species, but I am not sure that 
P. caementaria, Ducke is also. The learned entomologist of the Para 
Museum (Bolet, do Museu Goeldi, IV, 355) says of the latter :-—* cayennen- 
sis, Moebius !—* fulvofasciota, cayennensis et phthisica auctorum.’”’ It may 
be useful to give a description of our species. 
