426 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Worker. Length 4-9 mm. 
Resembling F. sanguinea. Body rather robust. Head subrec- 
tangular, about as long as broad, a little narrower in front than behind, 
with straight posterior and very feebly convex lateral borders. Man- 
dibles 8-toothed. Clypeus strongly carinate, with entire anterior 
border. Antennae rather stout, penultimate much thicker and shorter 
than the basal funicular joints. Pro- and mesothorax very convex, 
hemispherical. Mesoépinotal constriction pronounced; epinotum 
shaped much as in sanguinea, but more rounded and less angular. 
Petiole broad, compressed anteroposteriorly, with a sharp border, 
which is entire or feebly emarginate in the middle. Gaster large, 
broadly elliptical, legs long and robust. 
Body opaque; mandibles shining, finely striatopunctate; frontal 
area glabrous and shining. Gaster glossy or feebly shining. 
Pubescence fine and abundant; suberect hairs short, usually very 
sparse on the head and thorax, more abundant on the gaster. Gula 
almost always with a few erect hairs; eyes hairy. Tibiae with only 
a few minute slanting hairs in addition to the row of bristles on the 
flexor surfaces. 
Dark or pale red; front, vertex and antennae dark brown to blackish 
brown; clypeus sometimes with a median longitudinal brown streak; 
pronotum usually with a small brown or black spot not reaching the 
posterior border of the segment; gaster blackish brown, its base some- 
what reddish. 
FEMALE. Length 9-11 mm. 
Similar to the worker. Head and thorax opaque, but gaster very 
smooth and shining. Erect hairs short and sparse, absent on the 
gaster. Pubescence fine, most distinct on the legs and scapes. Red; 
front, vertex, mesonotum, the anal region, spots on the pleurae, tibiae, 
tarsi, tips of femora, middle of clypeus, and gaster, with the exception 
of its base, dark brown or black. Mandibles dark red, subopaque, 
coarsely striatopunctate. Wings slightly infuscated, with light 
brown veins and stigma. 
Mate. Length 9-11 mm. 
Body stout. Head rather small, mandibles edentate or very rarely 
dentate; masticatory border sharp, with apical point. Clypeus 
carinate, convex, with entire, angular anterior border. Petiole thick, 
its anterior and posterior surfaces flattened and its superior border 
very blunt, rounded and feebly excised in the middle. 
Body, including the frontal area, opaque, upper surface of gaster 
shining. 
Erect hairs black and dense on the head and thorax, sparse on the 
eyes and petiole, almost absent on the gaster. 
Black; genitalia, and legs, except the bases of the femora, yellowish 
or brownish red. Wings like those of the female. 
