- 237 — 



Mandibles shining, not striated; with 5 teeth; antennal club 3- 

 jointed , 3 



3. Anterior slope of petiole seen in profile nearly straight. . 4 

 Anterior slope of petiole seen in profile deeply concave . . 5 



4. Color reddish testaceous; mesonotuni convex and rounded. 



Lenjtli 7-9 mm. Bolivia, Peru balzani Emery. 



Color yellow; mesonotum flat and horizontal, not higher than 



the base of the epinotum. Length 8 mm. Brazil . . . duckei Forel. 



5. Occipital margin of head with an indistinctly raised border; 

 epinotum with a deep median excavation behind bordered on each si- 

 de by a large, rounded^ laterally compressed tubercle. Color rufo-tes- 

 taceous, with darker gaster. Length 6 8 mm. Costa Rica. 



foreli Emery. 



Occipital margin of head Avith a distinct raised border; epinotum 



with smaller, blunter and not lateral Ij^ compressed tubercles or none 



at all .... , 6 



6. Epinotal tubercles absent; longitudinal depression very faint 

 or absent; .... 7 



Epinotal tubercles present; longitudinal depression distinct. . 8 



7. Color rufo-testaceous; petiolar peduncle rather short, with a 

 small, acute, anteroventral spine; epinotum with a faint longitudinal 

 depression. Length 8-9.5 mm. Colombia, Panama, Costa Rica. 



leoninus Forel . 



Color piceous; petiolar peduncle longer, without anteroventral 



spine; epinotum without a trace of a longitudinal depression. Length 



10 mm. Peru staudingeri Emery. 



8. Piceous; both petiole and postpetiole Avithout anteroventral 

 teeth; epinotum with a pair of distinct tubercles and a distinct longi- 

 tudinal groove. Length 8 mm, Brazil nasutus Forel. 



Rufo-testaceous 9 



9. Basal surface of epinotum bordeied with two high, ear-like 

 lobes, between which it is deeply concave; petiolar node very large, 

 antero-posteriorly compressed and scale like, its peduncle short. Length 

 8-8.5 mm. Surinam emeryi Forel. 



Basal surface of epinotum Avith tAvo blunt ridges terminating be- 

 hind in blunt tubercles and separated by a shalloAv longitudinal de- 

 pression; petiolar node not enlarged and only moderately compressed 

 antero-posteriorly, its peduncle long. Length 7-8 mm. Brazil. 



Mtuherculatus Fabr. 



18. — Tetramorium (Tetrogmus) simillimum Fabr. 



Several workers from Cordoba. This common tropicopolitan 

 ant has not, I believe, been recorded Irom Mexico heretofore. 



