446 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
F. rufa subsp. obscuriventris Emery, Zool. jahrb. Syst., 1893, 7, p. 649; 
Wheeler, Ants, 1910, p. 570. 
F.. dryas Wheeler, Bull. Amer. mus. nat. hist., 1905, 21, p. 268, 8 9. 
WorkKER. Length 3.5-7.5 mm. 
Averaging smaller than the preceding subspecies. Base of epino- 
tum usually convex and rounded. Petiole moderately broad, strongly 
compressed anteroposteriorly, its dorsal border thin and sharp, entire 
and produced upward in the middle. 
Opaque; mandibles and clypeus slightly shining, longitudinally 
striate, frontal area very smooth and shining. Gaster subopaque or 
slightly shining, finely shagreened and punctate. 
Hairs and pubescence yellowish, the former short, erect, as abundant 
as in the typical truncicola, covering all parts of the body except the 
antennae; scapes sometimes with a few scattered hairs on their pos- 
terior surfaces. Eyes hairy. Pubescence distinct and rather dense 
on the head and thorax, sparser and finer on the gaster so that the 
surface is clearly visible. 
Deep red, when mature; mandibles and corners of clypeus darker; 
gaster black, with the anal region and sometimes also a small spot at 
the base of the first segment reddish. Large workers very rarely, 
smallest workers somewhat more frequently, with a brownish cloud 
in the region of the ocelli and on the pro- and mesonotum. 
FEMALE. Length 7-8 mm. 
Surface of body more shining than in the worker, especially the 
gaster, which is as glabrous and shining as in the female of the typical 
rufa. Mandibles coarsely striatopunctate, head and thorax very 
finely and densely punctate; clypeus, front, and anterior portion of 
mesonotum with several large, elongate punctures. 
Hairs longer and more flexuous than in the worker, especially on the 
top of the head, gula, thoracic dorsum, and tibiae, varying greatly 
in length, sparse on the pleurae and absent on the gaster, except on 
the ventral surface and tip. Antennal scapes often with a row of 
long, flexuous, erect hairs along their posterior surfaces. Eyes hairy. 
Pubescence yellowish, abundant and rather dense on the thorax and 
legs; sparse on the gaster. 
Deep red, three elongate spots on the mesonotum, the posterior 
portion of the scutellum, the metanotum, and the gaster black. 
Tibiae, tarsi, and funiculi dark brown. Anal region sometimes red- 
dish; first segment often with a yellowish red spot at the base. Wings 
strongly infuscated, with paler tips, brown veins and stigma. 
Mate. Length 8 mm. 
Mandibles edentate, rather narrow. Eyes large. Petiole more com- 
pressed anteroposteriorly than in the other subspecies, its border rather 
sharp and not excised. 
