WHEELER: ANTS OF THE GENUS FORMICA. 463 
surface of head without hairs. Pubescence on head and thorax dilute 
and very short, completely lacking on the mesonotum. Head broad 
behind and with a straight margin and rounded posterior corners. 
Clypeus broadly rounded, scarcely carinate, shining, feebly and ob- 
liquely striated. Mandibles shining, strongly age ya petiole 
cuneate, squarely truncated above. 
Host (Temporary). Probably F. fusca var. subsericea. 
Typr LocALity.— South Dakota: Hill City (Th. Pergande). 
British Columbia: Golden (W. Wenman). 
Nova Scotia: Digby (J. Russell). 
I have redescribed the worker of this species from a cotype. It is 
easily recognized by the shape of the head and especially by the 
petiole, which differs from that of all other species of Formica known to 
me. The palpi, too, as Emery has observed, are remarkably short. 
The specimens from the three localities mentioned above all agree in 
having extremely few or no hairs on the dorsal surface of the body 
and none on the gula, thus coinciding with Emery’s remark “superne 
haud pilosa,” so that the following form, which I first described as a 
distinct species and later regarded as identical with the typical dako- 
tensis, may be retained as a variety. 
51. F. DAKOTENSIS var. MONTIGENA Wheeler. 
F.. montigena Wheeler, Bull. Amer. mus. nat. hist., 1904, 20, p. 374, 8 92 o&. 
Worker. Length 3.5-6.5 mm. 
Differing from the worker of the typical dakotensis in having longer 
and more numerous erect hairs on the upper surface of the head, 
thorax, and petiole, and in having a few erect hairs on the gula. The 
pubescence on the gaster and legs seems also to be a little longer and 
more distinct. The gaster is more brownish or reddish and the base 
of the first segment is often yellow or red. 
FemMaLeE. Length. 7 mm. 
Mandibles and clypeus like those of the worker. Head large, as 
broad as long, its sides straight, slightly converging in front, its pos- 
terior angles rounded, its posterior border feebly excised. Thorax 
distinctly narrower than the head. Petiole extremely thick and blunt, 
its upper border transverse and feebly excised when seen from behind. 
Wings as long as the body (7 mm.). 
Body and legs very glabrous and shining. Mandibles coarsely 
striatopunctate. Clypeus delicately striated anteriorly. Antennae 
subopaque. = 
Hairs suberect, sparse, yellowish, longest on the gaster, especially 
