1903.] NATURAL SCIENCES OF PHILADELPHIA. 223 



Table for the identification of the workers of Leptothorax. 



1. Antennoe 11-jointed, -■ 



Antennae 12-jointed, ^^ 



2. Thorax with faint but distinct mesoepinotal constriction, 3 



Thorax without mesoepinotal constriction, ' 



3. Postpetiole sculptured, opaque, ^ 



Postpetiole smooth and shining above, o 



4. Tibice and antennal scape witliout clavate hairs, -5 



Tibise and antennal scape with short, erect, clavate hairs, 



L. hirticornis Emery. 



5. Hairs on body long and thin, not clavate, 



muscorum Nyl. var. sordidus var. nov. 



Hairs on bodv short and clavate, 



acervorum Mayr. subsp. canadensis Prov., etc. 



6. Tibia with clavate hairs, Proranc/im Emery. 



TibijB without clavate hairs, Emersom Wheeler. 



7. Epinotal spines very short, dentiform, 8 



Epinotal spines long " 



8. Petiole not conspicuouslv larger in profile than the postpetiole, 



Schaumi Roger. 



Petiole conspicuouslv larger in profile than the postpetiole, 



fortinodis Mayr. 

 (and its varieties). 



9. Dark-colored, with very long, horizontal epinotal spines, 



lo7igispinosus Roger. 

 Yellow, sometimes more of less infuscatcd; epinotal spines shorter, 



curvispinosus Mayr. 

 (and its subspecies and varieties). 



10. Without mesoepinotal constriction ; hairs on body clavate, not abundant, 11 

 With pronounced mesoepinotal constriction, hairs abundant, not clavate 



(subgenus Dicfu)thorax Emery), 19 



11 Head very largely smooth and shining, j-* 'i-' '^'^ 



Head opaque or subopaque, or smooth only along the median hne or 



behind, ^"^ 



12 Very dark-brown, or black, antennal scape almost reaching the posterior 



angle of the head, Schmittii sp. nov. 



Yellow, or somewhat infuscated; scape reaching to | the distance between 



the eye and the posterior corner of the head, niiens Emery 



(and its subspecies and variety). 



13. Anterior margin of clypeus entire, rounded, .... 14 



Anterior margin of clypeus sinuately excised, lb 



14. Head and thorax very coarsely reticulate-rugose, . . . texanus sp. nov_. 

 Head and thorax not coarsely reticulate-rugose, l-'5 



15. Clypeus produced, with angularly projecting anterior border, 



tricarinatus Emery. 



Clypeus not produced, with broadly rounded anterior border, 



neomexicanus sp. nov. 



16. Black or dark-brown species, Y^ 



Yellow species, ^^ 



5. L, petiolatus Forel, Ann. Soc. Ent. Belg., XLV, 1901, p. 129. ^ . Wheeler, 

 Ann. Soc. Ent. Belg., XLV, 1901, p. 201. 

 Cuernavaca, Mexico . "A single nest, consisting of a deiilated queen and about 

 25 workers in a Tillandsia in parabiosis with Cryptocerus and Cremasii- 

 garter." 



