270 Bulletin American Museum of Natural History. [Vol. XXI, 



Rockford, 111. They differ from the typical form in having naked 

 eyes and less hairy bodies. Some of the larger workers from the latter 

 locality are almost as naked as F. rufa subsp. integra. The smallest 

 workers from one of the Rockford colonies have the head and thorax 

 very deeply infuscated. 



3. Formica nepticula sp. nov. 



Worker. — Length, 4-6 mm. 



With the habitus of a small F. rufa. Mandibles 8-toothed. Palpi rather 

 long. Head, excluding mandibles, a little longer than broad, cheeks slightly 

 flattened, somewhat converging in front; posterior border straight, posterior 

 angles rounded. Clypeus strongly carinate, its anterior border angularly pro- 

 duced in the middle. Antennae of the rufa type. Thorax in profile with 

 deep mesoepinotal constriction ; pro- and meson otum rounded, hemispherical; 

 epinotum evenly rounded, without any angle. Petiole large, as high as the 

 epinotum, convex in front, more flattened behind, border rather sharp; seen 

 from behind the upper border is transverse in the middle and obliquely trun- 

 cated on either side, the lateral surfaces are straight and converge below. 

 Gaster and legs as usual. 



Head, thorax, and petiole subopaque, very finely shagreened; mandibles, 

 clypeus, and frontal portion of head, but especially the frontal area, more shin- 

 ing. Mandibles densely striated and coarsely punctate. Legs and gaster shining, 

 the latter finely and transversely shagreened, with the lustre of "watered" 

 silk. 



Hairs golden yellow, obtuse, suberect, and very sparse, on the upper and 

 lower surfaces of the head, upper surface of thorax, and on the gaster. There 

 are also a few scattered hairs on the flexor surfaces of the coxae, femora, and 

 tibiae. Eyes naked. Pubescence whitish, very short and sparse, but visible on 

 the antennae, sides of the thorax, and on the gaster where it fails to conceal 

 the shining surface. 



Mandibular teeth and gaster black ; remainder of the body and appendages 

 deep red; antennal funiculi, legs, especially the tibiae, mandibles, and antero- 

 lateral comers of the head, darker and more brownish. Ocellar region and 

 mesonotum slightly infuscated even in larger workers, but there is no increased 

 tendency to infuscation in the smaller workers. 



Female. — Length, 4-5 mm. 



Mandibles and clypeus like those of the worker, except that the latter is 

 more convex and less prominently keeled. Head slender, excluding the man- 

 dibles distinctly longer than broad, with long, anteriorly converging cheeks. 

 Thorax distinctly narrower than the head. Petiole similar to that of the 

 worker but with sharper superior border, often slightly notched in the middle. 

 Gaster small. Legs slender. Wings somewhat longer than the body (5.3 mm.). 



Body smooth and shining, very finely shagreened, back of head and meso- 

 notum more opaque; gaster very glabrous, being much more deUcately sha- 

 greened than in the worker. 



Hairs golden yellow, suberect, slender and obtuse, much longer than in the 

 worker and more abundant, especially on the upper surface of the head and 



