wheeler: ants of the genus formica. 485 



hairs and pubescence. There are prominent golden yellow hairs on 

 the clypeus, front, and vertex and on the dorsum of the pro- and 

 mesonotum, and the hairs on the gaster, which are also golden or 

 fulvous, are coarser. The pubescence is grayish and denser on all 

 parts of the body but especially on the gaster. This region is also 

 more coarsely shagreened and therefore subopaque or opaque and not 

 shining. The funiculi and the tips of the scapes are fuscous, in other 

 respects the color is like that of the typical form. 



Male. Length 7.5 mm. 



Differing from the male of the typical exsectoides in having the thorax 

 and gaster invested with longer pubescence and the mesonotum and 

 scutellum covered with more abundant subappressed hairs. Eyes 

 hairy. The single rather immature specimen examined has bidentate 

 mandibles. The petiole is broadly excised in the middle and its 

 margin has the form of a pointed, compressed tooth on each side of the 

 excision. 



Type locality. — Colorado : Breckenridge (Emery) . 



Colorado: Boulder (P. J. Schmitt and Wheeler); Florissant 

 (Wheeler). 



This is, in my opinion, a sharply marked subspecies and not a mere 

 variety. It is readily distinguished from the typical form also in its 

 habits. Its nests resemble those of the eastern form in size and shape, 

 but are made of earth and pebbles instead of earth and vegetable 

 detritus. At least this was the case with several nests which I saw 

 at Florissant. When these nests were situated near the railroad track 

 they were covered also with locomotive cinders which the ants had 

 carefully collected. All the nests examined were in open country, 

 not in woods. 



70. F. ulkei Emery. 



F. ulkei Emery, Zool. jahrb. Syst., 1893, 7, p. 653, pi. 22, fig. 7, S ; Wheeler, 

 Ants, 1910, p. 446, 570. 



Worker. Length 3.5-6 mm. 



Mandibles with 8 teeth on the apical and a few indistinct denticles 

 on the basal margin. Head, excluding the mandibles, distinctly 

 longer than broad, very slightly narrower in front than behind, with 

 broadly and deeply excised posterior border and rather straight sides. 

 Front convex, vertex less flattened than in exsectoides. Clypeus 

 carinate, but less acutely than in exsectoides, its anterior margin, 

 angularly produced. Frontal area triangular, a little broader than 

 long; frontal carinae at first diverging posteriorly but at their posterior 



