MEXICAN FORMICID^. 895 



striation of mandibles somewhat finer and denser. An- 

 tennse stout, the scape not quite reaching to the occiput. 

 Meso-metanotal constriction faint, the thorns stout, acute 

 and straight, directed back- and upward and diverging 

 towards the end; they are somewhat longer than the dis- 

 tance between them at base; declivity deeply concave, 

 and with an acute, rather long and broad tooth each side 

 of the insertion of the petiole of the first node. Nodes 

 very stout, the first one almost cubical, convex above and 

 at the sides, narrowest in front, with the anterior and pos- 

 terior face perpendicular. Second node transversely 

 oval, convex. Abdomen polished, the first segment 

 finely and densely granulated and sparsely punctured. 

 Erect hairs yellowish, shortest and stoutest on the abdo- 

 men, legs and antenna. 



Fourteen specimens. Sierra San Lazaro, Cape Re- 

 gion, Lower California. 



45. Cyphomyrmex flavidus n. sp. 



Worker: Length, 2.2—2.8 mm. Head, as usual in this 

 genus; the antennal grooves deep and extending to the 

 apex of the lateral angles of the occiput, the frontal car- 

 inae with a deep and rounded emargination opposite the 

 eyes; the occiput obtusely and deeply emarginate, the 

 vertex with a depressed and flattened triangular area at 

 the posterior angles and a circular area each side of the 

 triangular frontal area. Clypeus slightly arcuate ; the 

 scape of the antenna reaching slightly beyond the apex 

 of the posterior angles; joints two to seven of the flagel- 

 lum about as long as broad. 



Pronotum convex above, carinated laterally and pro- 

 vided each side, posteriorly, with a prominent, stout and 

 obtusely rounded tubercle, and with an acute angle ante- 

 riorly at insertion of the coxse. Mesononotum oval and 

 with a longitudinal furrow, the margins bordering it, 



