The Hymenoptera of the Georgetown Museum. 217 
Megacanthopus atriceps, sp. n. 
Dark rufo-testaceous, the head except the malar space, the prothorax except 
the base all round and a line round the apex of the pronotum, the mesonotum, 
the mesopleurz except a triangular spot at the tegule and a larger oblique one 
down the middle and a line on the base of the metapleure at the top, black ; 
the dilated part of the abdomen infuscated, the legs are lighter coloured than 
the thorax ; wings fuscous violaceous, the stigma testaceous, the nervure 
black ; the basal abscissa of the radius slightly longer than the following 
2 united, the 2nd one quarter of the length of the 3rd; the 2nd recurrent 
nervure straight, obliquely sloped in front, below the middle broadly rounded 
outwardly, the hinder part obliquely bent towards the base. Base of thorax 
transverse, margined, the sides slightly projecting. Abdominal petiole slightly, 
but clearly shorter than the thorax, and as long as the following 2 segments 
united. Female.—Clypeus a little longer than wide, the apex at the sides 
roundly narrowed, the centre transverse. Malar space slightly longer than the 
2nd antennal joint. Antenne black, rufous below, the 3rd joint entirely so. 
Megacanthopus ruficornis, sp. n. 
Black, smooth, shining covered with a minute pile, the mandibles and 
flagellum of antennee rufous. Wings fulvous hyaline, darker along the costal 
cellule, the hinder paler than the anterior, the stigma and nervures bright 
reddish fulvous ; the 1st abscissa of the radius, not much shorter than the 4th 
and fully one fourth than the 2nd and 3rd united, the 2nd not one fourth of 
the length of the 3rd and less than the space between the 2 recurrent nervures; 
the anterior two-thirds of the 2nd recurrent roundly, slightly obliquely bent 
backwards, the hinder third straight, oblique, forming a rounded angle with 
the anterior. Base of thorax transverse, raised, the edges distinctly project- 
ing into a rounded angle. The depression on the metanotum forms a longish 
oval, with a narrow, but distinct furrow in the centre. Petiole stout, the 
basal third narrowed, not one half the length of the thorax, about as long as 
the post-scutellum and metanotum united, about one quarter longer than 
the 2nd segment. Female. Length 17 mm. 
Cypeus not much longer than wide, shining, sparsely, distinctly punctured, 
the apex broadly and roundly projecting. Front and vertex opaque, aluta- 
ceous, densely covered with short black pubescence. Thorax moderately 
shining, densely covered with short, fuscous pubescence, as is also the 
abdomen, especially towards the apex. 
Megacanthopus violaceipennis, sp. n. 
Black, densely covered with a white pile, the coxe and troehanters dark 
testaceous ; wings dark fuscous violaceous, the violaceous tint, lighter at 
the apex, the nervures and stigma black, the 1st abscissa of radius as long as 
the 2nd and 3rd united, the 2nd one-quarter of the length of the 8rd and 
slightly more than half of the length of the space between the recurrent ner- 
vures. Base of thorax bluntly rounded, narrowly, but clearly keelea, the 
sides rounded. Metanotal keel commencing at the base, where it is narrow ; 
it then becomes gradually widened to the apex. Clypeus distinctly longer 
