1922] Ants of the Genus Formica in the Tropics 175 



Arizona and California. Some of these together with a few 

 alHed species occur also in Mexico, but apparently only at 

 elevations of about 8000 ft., as far south as Hidalgo in the state 

 of Guerrero (lat. 18°). In all probability the same Formicas 

 inhabit the mountains of the state of Oaxaca and therefore 

 extend the range of the genus to the southern limits of the 

 Nearctic Realm, that is to the Isthmus of Tehuantepec. 



Although there would seem to have been every opportunity 

 both in Asia and Mexico for the spread of the species of P'ormica 

 into the tropics, the only recorded instances of its occurrence 

 are the following: 



(1) Bingham in 1903 cites the taking of three workers and 

 a female of the common European F. rufiharhis Fabr. by W. 

 L. Distant in Pretoria, South Africa, only a short distance from 

 the tropic of Capricorn (26° S.). This seems to be the only 

 record of the genus occuring in the southern hemisphere. There 

 would seem to be little doubt that the species was imported 

 directly from Europe. 



(2) According to Emery F. fuscn yely. glebaria, a common 

 ant in central and southern Europe, has been imported into the 

 gardens of Algiers. He calls attention to the fact that this insect 

 does not occur in Crete nor on the smaller islands of the Mediter- 

 ranean. 



(3) In 1913 Forel described a var. formosae of F. jiicea 

 Nyl. from Taihorin, Formosa, which is on the tropic of Cancer. 

 F. picea is a boreal European ant, usually found in peat-bogs. 

 Forel's variety may perhaps occur at a considerable elevation 

 in the mountains, which in Formosa rise to an altitude of 9000 

 to 14,000 ft. In this case, therefore, we may be dealing with a 

 relict instead of a recent importation like the two previous cases. 

 Emery believes that the F. fusca var. filchneri described by 

 Forel from China is really F. picea. 



I was astonished to find among a fine collection of ants made 

 for me by Dr. J. W. Chapman at Dumaguete, on the island of 

 Negros Oriental, Philippines, several specimens of two species 

 of Formica. One of them, represented by a number of workers, 

 agrees in all respects with European and North American 



