224 PROCEEDINGS OF THE ACADEMY OF [Feb., 



17. Petiole slender, seen from above three times as long as broad, node A-erj;- 



low and rounded, obturator sp. nov. 



Petiole only U times as long as broad; node higher and shorter, 



nevadensis sp. nov. 

 IS. Head opaque throughout, petiolar node round in profile ; length 1.5-1.75 mm., 



terrigena sp. nov. 

 Head with a smooth median line, node of petiole somewhat angular; length 



2.25, • Andrei Emery. 



19. Summit of petiolar node seen from behind impressed or concave, 



Pergandel Emery, 

 Summit of petiolar node seen from behind convex, rounded, 



jloridanus Emery. 



1. Leptothorax hirticoruis Emery. 



L. hirticornis Emerv, Zool. Jahrb. Abth. f. Svst , YIII, 1S94, pp. 317 and 

 319. ^. ' 



Worker. — Length 2.75 mm, 



Clypeus hardly impressed in the middle. Antenna? 11-jointed, joints 

 2-7 of the funiculus shorter than broad, club but relatively little thick- 

 ened. Thorax slender, distinctly impressed at the mesoepinotal 

 suture. Epinotal spines of average size, pointed, strongly com- 

 pressed. Petiole robust, its anterior and posterior dorsal slopes form- 

 ing a slightly obtuse angle; seen from above the sides of the petiole 

 are subparallel. Postpetiole small, almost trapezoidal, a little broader 

 than long. 



Clypeus somewhat shining. Head, thorax and pedicel opaque, 

 densely foveolate-punctate, the upper surface of the head also finely 

 and rather regularly longitudinally rugose. 



Hairs very short, strongly clavate, erect, not only covering the 

 body but also the antennal scape and legs. 



Bright testaceo-ferruginous, gaster and middle of front infuscatcd. 



Type locality: Washington., D C. (Pergande). 



Described from a single specimen in the collection of Prof. Emery. 



2. Leptothorax muscorum Nylander, var. sordidus var. nov. 



L. muscorum Emery, Zool. Jahrb. Abth. f . Sj^st., VIII, 1S94, p. 31S. ^ . 



Worker (PL XII, fig. 2).— Length 2-2.75 mm. 



Clypeus not impressed in the middle, its anterior border nearly 

 straight, not produced. Antennae 11-jointed; scape reaching to mid- 

 way between the eye and the posterior angle of the head ; first funicular 

 joint as long as joints 2-4 together, terminal joint as long as the two 

 preceding joints of the club. Thorax broad in front, Avith rounded 

 humeri, much narrower behind, with a distinct mesoepinotal con- 

 striction. Epinotal spines of moderate length, directed backward, 

 and slightly outward, about as far apart at their bases as they are long. 

 Petiole from above suboblong, with slightly convex sides, nearly 



