MEXICAN FORMICID^E. 89 J 



margin of the clypeus, the teeth and external edge of the 

 mandibles and the abdomen black. 



Eight specimens. San Jose del Cabo. 



41. ISCHNOMYRMEX MEXICANUM n. Sp. 



Worker: Length, 7 mm. Head elongated and more 

 than twice as long behind than in front of the eyes, ta- 

 pering to a neck and terminating in a sharp and elevated 

 collar. Frontal area triangular and depressed. Clypeus 

 transversely triangular, its posterior angle rounded, the 

 lateral pieces deeply sinuate, the anterior margin arcuate 

 and broadly emarginate at the middle. Mandibles armed 

 with three stout teeth at the apex and a series of smaller 

 teeth behind them. Prothorax about one-half as broad 

 as the head in the region of the eyes, prolonged anterior- 

 ly into a neck, the mesonotum with a shallow, transverse 

 depression beyond the middle; metathorax much elon- 

 gated, its basal section about four times the length of the 

 declivity, it is nearly straight above and with a shallow, 

 longitudinal channel along the middle, the spines are short, 

 stout and toothlike. Nodes rather stout. Legs very long 

 and slender, the first tarsal joint of the posterior legs at 

 least as l6ng as the tibiae. 



Head, densely granulated, its anterior half somewhat 

 irregularly rugoso- striate, with the striee between the 

 frontal carinie somewhat finer; there is also a deep, elon- 

 gated, median depression just beyond the carinse; frontal 

 area with a median and several posteriorly converging car- 

 inse; clypeus indistinctly granulated; mandibles quite 

 densely striated and sparsely punctured. Prothorax pol- 

 ished, faintly shagreened and very sparsely punctured; 

 the mesonotum granulated along the middle, the anterior 

 lateral half obliquely striated and the posterior half dense- 

 ly granulated ; surface of the metathorax quite coarse and 

 transversely rugoso-striate, the stri^ at the sides, poste- 



