wheeler: ants of the genus formica. 481 



yellow. In many specimens the upper surface of the head is more 

 reddish than the remainder of the body but there is little difference in 

 coloration between the smallest and largest workers. 



Type locality. — Massachusetts: South Natick (A. P. Morse). 



The position of this species is problematic, as the female is unknown, 

 but the characters of the worker certainly ally it to the preceding 

 forms of the microgyna group. It differs from all of these species in 

 its peculiar color and sculpture, the greater convexity of the posterior 

 portion of the head and the shape of the petiole. It must be a rare 

 species as I have been unable to find it again, even with Mr. Morse's 

 assistance, in the type locality. 



Exsecta Group. 

 66. F. exsectoides exsectoides Forel. 



F. Integra Mayr, Verh. Zool. hot. ver. Wien, 1862, 12, p. 70; Ibid., 1886, 36, 



p. 425, 9 cf (nee Nylander). 

 F. exsectoides (Forel) McCook, Trans. Amer. ent. soc, 1877, 6, p. 252-296, 



figs. 2-5, pis. 2-6; Proc. Acad. nat. sci. Phila., 1877, p. 135; Amer. natur., 



1878, 12, p. 431-345, 8 figs.; Proc. Acad. nat. sci. Phila., 1879, p. 154-156. 

 F. exsectoides Forel, Ann. Soc. ent. Belg., 1886, 30, C. R. p. xxxviii, ^ 9 ; 



Dalla Torre, Catalog. Hymen., 1893, 7, p. 195; Emery, Zool. jahrb. 



Syst. 1893, 7, p. 653, pi. 22, fig. 6; Wheeler, Bull. Amer. mus. nat. hist., 



1906, 22, p. 71, 403-413, pis. 43-48. 



Worker. Length 4.5-7.5 mm. 



Mandibles with the apical border 8-toothed, the basal border with 

 two or three minute and often very indistinct or obsolete denticles. 

 Head, excluding the mandibles as broad as long, a little narrower 

 in front than behind, with deeply excised posterior and nearly straight 

 lateral borders. Front convex, vertex flattened. Clypeus strongly 

 carinate, with anterior border entire and angularly projecting in the 

 middle. Frontal area distinct, frontal carinae moderately diverging. 

 Antennae slender, scapes not thickened towards their tips, funiculi 

 with the four basal joints somewhat longer and more slender than the 

 penultimate joints. Maxillary palpi moderately long, 6-jointed. Pro- 

 and mesonotum distinctly flattened above, mesoepinotal constriction 

 rather shallow; epinotum with subequal base and declivity, each 

 straight in profile and meeting at a rounded obtuse angle. Petiole 

 high and broad, compressed anteroposteriorly, with flattened anterior 

 and posterior surfaces, and sharp, cultrate border, which, seen from 



