1903.] NATURAL SCIENCES OF PHILADELPHIA. ^249 



shinino-, somewhat foveolate-punctate. Head subopaque except along 

 a broad median strip, extending from the frontal area to the occiput, 

 and on the posterior angles. These regions are smooth and shining. 

 Clieeks and sides of head rather delicately and longitudinally reticu- 

 late-rugose. On the front and vertex there are also a few rather large 

 indentations at widely separated intervals. Thorax nearly opaque, 

 in front delicately and evenly reticulate-rugose ; on the epinotum and 

 pleurse the rugte are coarser and have a distinctly' longitudinal trend. 

 Petiole and postpetiole nearly opaque, finely reticulate-rugose. Gaster 

 very smooth and shining. 



Hairs rather sparse, sil very- white ; those on the body subclavate, 

 shorter and more erect on the head and thorax, longer and more 

 reclinate on the pedicel and gaster. Hairs on the legs and antennie 

 short, non-clavate, appressed. 



Black. In some specimens the pedicel and thorax are dark-brown. 

 Scape and funiculus of antennae brown. Mandibles yellow, with black 

 teeth. Legs yellow, middle portion of the femora and tibiae and 

 terminal tarsal joint on each foot, black. 



Type locality: Manzanares, N. M. 



Described from five specimens taken by Miss Mary Cooper. The 

 species is obviously closely related to L. tricarinatus Emery, and 

 may prove to be merely a subspecies of this form. To judge from 

 Emery's description, the head of tricarinatus is more opaque, the 

 mesonotum shining, the first funicular joint larger than the three suc- 

 ceeding joints, the remaining joints of the funiculus shorter than broad. 

 Apparently, also, the postpetiole is considerably larger than in neo- 

 mexicanus. 



15. Leptothorax obturator sp. nov. 



Worker (PL XII, fig. 19).— Length 2.25-2.75 mm. 



Mandibles 5-toothed. Clypeus rather flat, its anterior margin 

 broadly truncated in the middle. Antennae 12-jointed ; scape reaching 

 posterior angle of head; first funicular joint as long as the three suc- 

 ceeding joints; joints 3-S broader than long, joints 9-11 forming a 

 club, the ninth distinctly narrower and shorter than the tenth, the 

 terminal joint longer and considerably thicker than the two preceding 

 joints. Thorax slender, somewhat broader in front than behind; 

 rounded at the humeri, in profile convex in front and slightly concave 

 behind on the dorsal surface, without mesoepinotal constriction. 

 Epinotal spines small, rather acute, not longer than broad at their 

 bases, nor further apart than long, directed upward. In front and 



