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Journal New York Entomological Society. [Voi. xvn. 



5- Leptothorax furunculus, new species. 



JVorker. — Length 2-2.6 mm. 



Head longer than broad, subrectangular, with very feebly emarginate posterior 

 border and slightly convex sides, with the eyes slightly in front of their middle. Man- 

 dibles 6-toothed. Clypeus convex, with rounded, entire, rather projecting anterior 

 border, its disc with a longer median and a pair of shorter lateral carinse. Antennae 

 1 2-jointed ; scapes not reaching the posterior corners of the head ; first funicular 

 joint as long as joints 2-5 together ; joints 2-7 narrow, subequal, broader than long, 

 joint 8 as long as broad ; club 3-jointed, its two basal joints subequal, together shorter 

 than the terminal joint. Thorax somewhat narrower behind than in front, with 

 rounded humeri ; dorsum flattened, with a distinct mesoepinotal suture and impres- 

 sion. Epinotal spines about as long as broad at their bases, rather acute, further apart 

 than long, directed upward and slightly outward and backward. Petiole nearly twice 

 as long as broad, slightly broader behind than in front, with straight sides; in profile 

 with rather thick peduncle, armed with an acute antero-ventral tooth ; node high and 

 acute, its anterior declivity concave, the posterior shorter, more abrupt and feebly 

 convex. Postpetiole subrectangular, a little broader than the petiole and somewhat 

 broader than long, with subparallel sides and distinct anterior angles ; in profile with 

 low, rounded node. Gaster rather large, elliptical, with rounded anterior corners. 

 Legs of usual shape. 



Mandibles opaque, indistinctly striato-punctate. Clypeus and frontal area shin- 

 ing, sides of the former longitudinally rugulose. Head, thorax, petiole and postpeti- 

 ole subopaque or glossy ; gaster glabrous, legs somewhat less shining. Head very 

 finely longitudinally rugulose and reticulate. Thorax, petiole and postpetiole cov- 

 ered with dense, shallow punctures, thoracic dorsum also very indistinctly and longi- 

 tudinally rugulose. 



Hairs yellow ; on the body sparse, erect, obtuse but hardly clavate ; on the legs 

 and scapes replaced by delicate appressed pubescence. 



Yellow ; thorax, petiole and postpetiole pale brown ; head, excluding the man- 

 dibles, clypeus, cheeks and gula, dark brown ; gaster dark brown or blackish above, 

 with the posterior edge and a broad band across the anterior portion of each segment, 

 yellow. Antennal clubs slightly infuscated. Mandibular teeth black. 



Described from a number of specimens which I took from a single 

 colony under a stone in Williams Caiion, near Manitou, Colorado, at 

 an altitude of about 7,500 feet. 



This species differs from all our other North American species of 

 Leptothorax vi'xXh. 1 2-jointed antennae (except those of the subgenus 

 Dichothorax) in having a distinct mesoepinotal impression. It resem- 

 bles Z. tricarinatiis Emery in the structure of its clypeus, but its peti- 

 ole and postpetiole are very different, and the color of the body is 

 much paler. The surface of the head, thorax and pedicel have a 

 peculiar oily appearance which I have not observed in any of our other 

 species of the genus. 



