203 



with heads inlermediate in size between the typical soldiers and tho 

 workers. 



22. Pheidole Kingii André, var. instabilis Emery. 

 Cuernavaca, Dec. 25-27. Common in smaU colonies under half-dried 



cow-dung. The soldiers are highly polymorphic, exhibiting ail tran- 

 sitions in the size and shape of the head to the worker form. Stores 

 Lip grass-seeds in its nest like P. pilifer. The Mexican form should, 

 perhaps, constitute a.variety of the Texan species, whioh is decidedly 

 larger, forms more flourishing colonies, and lives nnder stones; 

 never, so far as observed, under cjw-dung. 



23. Solenopsis geminata Fabr. 



The « fire ant », common at Cuernavaca, Queretaro and Aguas 

 Galientes, as elsewhere throughoat the tropics. Stores grass-seeds 

 like many species of Pheidole, and stings severely. Spécimens taken 

 in the above mentioned localities agrée in coloring with the typical 

 form fouod throusrhout Central Texas. 



"■■n' 



24. Solenopsis molesta Say. 



Cuernavaca, Dec. 26. Not hitherto recorded from Mexico. Lives as 

 a theif-ant in the nests of Odontomachus clarus just as it lives with 

 this and other large ants throughout large portions of the United 

 States. 



25. Cremastogaster opaca Mayr, var. dentinodisForel. 



Queretaro Dec. 30. Common under stones on the dry hills about 

 the town. 



26. Cremastogaster brevispinosa Mayr, var. minutior 

 Forel. 



Cuernavaca, Dec. 26-27. Common everywhere, running in loose 

 files on the trunks and branches of the trees. It nests in ihe Tilland- 

 sias, often in parabiosis with other ants. It forms perforated parti- 

 tions consisting of a black paper-like substance between the over- 

 lapping leaves of the epiphytes. One nest was also found in the cup- 

 shaped cavity of one of the singular flower-like, woody excrescences 

 on the guava trees. The :uits had closed up the wide opening of the 

 cup with an even layer of the papery substance, leaving a small ori- 

 fice near its center to serve as an entrance. 



27. Pseudomyrma Kunckeli Emery. 



Cuernavaca. Dec. 27. Found running on the trunks and branches of 

 small acacias and living in the dry twigs of the same trees. When 

 irritated thèse ants approach with their abdomens flexed to one side 



