MANN: ANTS OF THK IJUITISII SOLOMON ISLANDS. 323 



51. Crematogaster obnigra, sp. nov. 



Worker. Length 2.25-3 mm. 



Head subquadrate, longer than broad, shallowly convex behind, with 

 rounded occipital corners. Mandibles 4-dentate. Anterior border of clypeus 

 concave. Antennal scapes extending to half the distance between posterior 

 border of eyes and occipital corners; funicular joints two to seven about as 

 broad as long; club slender, terminal joint longer than the two preceding 

 joints. Eyes little convex, situated at sides of head slightly posterior to middle. 

 Thorax robust. Pronotum with rounded sides and humeri. Promesonotal 

 impression indistinct. Mesonotam in profile evenly and rather feebly convex; 

 sides rounded. Base of epinotum massive, convex, distinct from declivity, 

 which is one and one half times as long as base and almost fiat; spines stout; 

 triangular, broader at base than long. Petiolar node slightly longer thfin 

 broad, broadest in front of middle, with narrowly rounded and elevated sides. 

 Postpetiole broader than long, broadly impressed at middle. 



Shining. Mandibles coarsely striate. Ch^seks, anterior half of pronotum, 

 sides of mesonotum, base of epinotum and meso- and metapleurae striolate. 

 Petiole and postpetiole punctate, the former densely so. 



Pilosity moderately abundant, and suberect on head, thorax, abdomen, 

 legs, and antennae. 



Color dark brown to black; mandibles and tarsi fuscous. 



Russell: West Bay. 

 Type.— U. C. Z. 9,168. 



Key. 



Epinotal spines very short; thorax rounded at sides, not margined; base 

 of epinotum separated from declivity by broadly rounded margin; 

 color black obnigra Mann. 



Epinotal spines at least half as long as the distance between their bases; 

 thorax, at least in part, margined or submargined; base and declivity 

 of epinotum, not separated 1- 



1. Smaller species (length 2 mm.); hxmieri angulate; mthout pilosity; bi- 



colored, gaster jet black, the rest brownish red elysii Mann. 



Length 2.25-3 mm. humeri rounded, not bicolored 2. 



2. Petiolar node broadest behind; clj^Jeus bicostate; pronotum and meso- 



notum sharply costate; gaster unusually long and slender, .foii Mann. 



Petiolar node broadest in front; thorax not costate; gaster of ordinary 



form 3- 



