wheeler: ants of the genus formica. 477 



than the head through the eyes. Base of epinotum with a median 

 longitudinal impression, metanotum concave. Petiole very thick 

 and blunt above, anterior and posterior surfaces both convex, border 

 with a faint median notch. 



Head, thorax, legs, and antennae subopaciue, finely shagreened; 

 mandibles, clypeus, frontal area, vertex, and scutellum shining as are 

 also the petiole and especially the gaster. 



Hairs and pubescence grayish, the former short and erect on the 

 clypeus, thorax, gaster, and legs; the latter sparse and indistinct 

 except on the antennae and legs. Eyes almost imperceptibly hairy. 



Black; mouthparts, legs, and genitalia fuscous. Wings like those 

 of the female but of a slightly darker tint. 



Host (Temporary). Probably F. neogagatcs. 



Type locality. — Connecticut: Colebrook, 1,400 ft. (Wheeler). 



Massachusetts: Stony Brook Reservation, Chestnut Hill, near 

 Boston (Wheeler). 



Illinois: Black Hawk Springs, near Rockford (Wheeler). 



The female nepticula resembles the female ncvadensis, but differs 

 in having much fewer erect hairs on the antennal scapes and body and, 

 owing to the nearly complete absence of grayish pubescence, a more 

 shining head and thorax. Moreover, the head, thorax, and appendages 

 are decidedly darker and less red than in nevadensis. The worker 

 nepticula may be readily confounded with that of F. truncicola ob- 

 scuriventris owing to both forms ha\ang the same color and the same 

 luster of the gaster, but ncpiicula is of average smaller size, has much 

 sparser, coarser, and more obtuse hairs, the border of the cl;yT)eus is 

 more projecting, and the epinotum is much lower and rounder. 



F. nepticula is, in my experience, a rare ant. It nests in open woods 

 under stones, the edges of which it banks with vegetable detritus. 

 The colonies are rather small. The males and diminutive females 

 make their appearance early in July. 



63. F. DiFFiciLis Emery. 



F. palUdefulva Mayr (nee Latreille), Verb. Zool. hot. ver. Wien, 1866, 16, 



p. 889, 9 . 

 F. rufa subsp. difficilis Emery, Zool. jahrb. Syst., 1893, 7, p. 651, pi. 22, 



figs. 9, 14, y 9 &. 

 F. difficilis Wheeler, Bull. Amer. mus. nat. hist., 1904, 20, p. 348; Ibid., 1906, 



22, p. 63. 



Worker. Length: 3.5-5.5 mm. 



Head, excluding the mandibles, slightly longer than broad, slightly 



