June, 1909.] Wheeler: North American Formicid^. 81 



of the epinotum, postpetiole and base of the gaster. The Brazilian 

 species has the epinotum coarsely rugose, the postpetiole reticulate- 

 rugose and the base of the gaster longitudinally striated. From P. 

 {E.) imberbiculus, townsendi ^\^QX<a in the sculpture of the postpetiole 

 and gaster and the greater opacity of the whole body ; from/Zwa in 

 having prominent teeth on the clypeus, in the reticulate rugosity of 

 the petiolar node, the sculpture of the head, etc. 



4. Leptothorax melanderi, new species. 



Worker. — Length 2 mm. 



Head rectangular, a little longer than broad, with straight, subparallel sides, 

 straight posterior border and eyes in the middle of the sides. Mandibles apparently 

 6 toothed. Clypeus moderately convex, with broadly rounded, entire anterior bor- 

 der, not produced in the middle. Antennae i2-jointed ; scapes reaching to the pos- 

 terior corners of the head ; first funicular joint as long as joints 2-5 together ; joints 

 2-S small, subequal, decidedly broader than long; club 3-jointed, its two basal joints 

 subequal, together shorter than the terminal joint. Thorax rather robust, with rounded 

 humeri and without mesoepinotal suture or depression ; in profile the dorsum is uni- 

 formly and feebly rounded. Epinotal spines stout, acute, longer than broad at their 

 bases and nearly as long as their distance apart, directed backward and slightly out- 

 ward and upward. Petiole about I j^ times as long as broad, broader behind than in 

 front, in profile conical, with rather acute apex, its anterior declivity concave and 

 longer than the posterior declivity which is more abrupt and slightly convex ; antero- 

 ventral tooth of peduncle prominent and acute. Postpetiole from above subrectangu- 

 lar, about 133 times as broad as the petiole, and l J4 times as broad as long, slightly 

 broader in front than behind, with distinct anterior angles ; in profile convex in front 

 above, depressed behind. Gaster elliptical, rather convex, with rounded anterior 

 corners. Legs of the usual shape. 



Opaque ; gaster glabrous and streak down the middle of the head and clypeus 

 slightly shining. Mandibles coarsely striato-punctate. Clypeus and head finely, 

 longitudinally rugose, the latter under a higher magnification also minutely reticulate. 

 Thorax, petiole and postpetiole uniformly and densely punctate. 



Hairs white ; sparse, erect and clavate on the body ; slender pointed and ap- 

 pressed on the mandibles and appendages ; longer and more oblique on the femora 

 than on the tibice. 



Dark brown ; gaster black ; mandibles, clypeus, cheeks, gula, appendages, neck 

 and articulations of pedicel brownish ; femora infuscated in the middle. Mandibu- 

 lar teeth black. 



Described from a single specimen taken by Mr. A. L. Melander 

 on Moscow Mountain, Idaho. 



This species is closely related to L. nevadensis Wheeler, but differs 

 in being more opaque, of a darker color, in having joints 2-8 of the 

 funiculus shorter, the clypeal margin entire, the thorax less narrowed 

 behind and the nodes of the petiole and postpetiole of a different 

 configuration. 



