494 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
but the differences of structure and habit seem to me to be sufficient 
to entitle it to the rank of a species, as it was originally described by 
Adlerz. According to this observer it does not build mound-nests 
like the typical exsecta and its subspecies and varieties but resembles 
F. truncicola in establishing its formicaries in rotten stumps or logs 
which it banks with fine vegetable detritus. 
Fusca Group. 
80. F. rusca Fusca Linné. 
F. fusca Linné, Syst. nat. ed. 10, 1758, 1, p. 580; Fauna Suec., ed. 2, 1761, 
p. 426; deGeer, Mem. hist. ins., 1771, 2, p. 1, pl. 42, figs. 12-15; Fabri- 
cius, Spec. ins., 1781, 1, p. 490; Mantissa ins., 1787, 1, p. 308; Olivier, 
Encycl. meth. insect., 1791, 1, p. 493; Fabricius, Ent. syst., 1793, 2, 
p. 352; Latreille, Essai hist. fourmis France, 1798, p.39, 8 2 @; Hist. 
nat. fourmis, 1802, p. 159, pl. 6, fig. 32,e 8 9 o; Fabricius, Syst. Piez., 
1804, p. 399; Latreille, Gen. Crust. ins. 1809, 4, p. 126; Lepeletier, Hist. 
nat. insect. Hymén., 1836, 1, p. 205, 8 @ o; Westwood, Introd. mod. 
class. insects, 1840, 2, Synop., p. 83; Nylander, Acta Soc. Fennica, 
1846, 2, p. 917, 919, 8 2 o&, pl. 18, fig. 23; Ibid., 1849, 3, p. 27, 30; 
Forster, Stettin. ent. zeit., 1853, 14, p. 141; F. Smith, Trans. Ent. soc. 
Lond., 1855, ser. 2, 8, p. 104, 8 @ &, pl. 9, fig. 15; Mayr, Verh. Zool. 
bot. ver. Wien, 1855, 5, p. 346, 8 @ o; Nylander Ann. sci. nat. Zool., 
1856, ser. 4, 5, p. 65, 8 2 o; F. Smith, List Brit. anim. Brit. mus., 
1858, pt. 6, p. 5, pl. 3, fig. 14; Meinert, Natur. abh. Dansk. vid. selsk., 
1860, ser. 5, 5, p. 44, 8 @ o; Mayr, Europ. Formicid., 1861, p. 47-49, 
8 9 o; Taschenberg, Hymen. Deutschl., 1866, p. 239; Forel, Denks. 
Schweiz., gesell. naturw., 1874, 26, p. 53, 56, 58, 356, 8 Q co; Bull. Soc. 
Vaud. sci. nat., 1875, ser. 2, 14, p.60; Lubbock, Journ. Linn. soc. Zool., 
1877, 13, p. 217, pl. 17, fig. 3; Ern. André, Spec. Hymén. Europe, 1882, 2, 
pt. 14, p. 182, 186, 190, pl. 5, fig. 12, 8 9 o; Adlerz. Bih. Svensk. vet. 
akad. Handl., 1886, 11, p. 286, 290, 8 9 o; Wasmann, Deutsch. ent. 
zeitschr., 1887, 31, p.109; Dalla Torre, Catalog. Hymen., 1893, 7, p. 196; 
Ruzsky, Formicar. Imper. Ross., 1905, p. 373, 1 fig.; Emery, Deutsch. ent. 
zeitschr., 1909, p. 198, 8 92 o; Ibid., 1912, p. 672. 
F. fusca var. glacialis Wheeler, Bull. Amer. mus. nat. hist., 1908, 24, p. 624, 
Lo Sous 
WorkKER. Length 4-6.5 mm. 
Body rather slender. Head longer than broad, narrower in front 
than behind, with straight posterior and lateral borders. Eyes large. 
Mandibles 8-toothed. Clypeus sharply carinate its entire length, 
