PSYCHE 



VOL. XVIII. JUNE, 1911. No. 3. 



TWO FUNGUS-GROWING ANTS FROM ARIZONA.' 

 By William Morton Wheeler. 



In a recent paper on the North American fungus-growing ants ^ 

 I based a new species of Trachymyrmex (T. arizonensis) on some 

 male and female specimens taken by Mr. Charles Schaeffer at 

 Palmerlee in the Huachuca Mts. of Arizona. Owing to the 

 absence of worker specimens, the status of this species has re- 

 mained somewhat problematical. At any rate, there was a 

 possibility that it might be merely a sub-species or variety of T. 

 saussurei described by Forel many years ago from Orizaba, 

 Mexico ' and subsequently taken as far north as Tepic by 

 Eisen and Vaslit.^ I was pleased therefore to find during 

 the past November in the type locality a number of col- 

 onies of T. arizonensis and to be able to learn something 

 of its habits. Both these and the characters of the worker 

 show that the species is valid and sufficiently distinct from 

 our other North American Trachymyrmex (saussurei Forel, septen- 

 trionalis McCook, turrifex Wheeler and jamaicensis Ern. Andre). 



Somewhat later in November 1910, I came upon a few colonies 

 of a small undescribed Trachymyrmex in the desert near Tucson, 

 Arizona. Descriptions of the workers of this and of T. arizonensis, 

 together with some notes on their habits are contained in the follow- 

 ing paragraphs : 



1. Atta (Trachymyrmex) arizonensis Wheeler (Fig. 1.) 



Worker. Length 3.5-5 mm. 



Head, without the mandibles, as broad as long, broader behind than in front, 

 with feebly concave posterior and feebly convex lateral borders and blmitly angular 

 posterior corners. Eyes hemispherical, in front of the middle of the head. Man- 



' Contributions from the Entomological Laboratory of the Bussey Institution, Harvard 

 University. No. 37. 



2 The Fungus-Growing Ants of North America. Bull. Amer. Mus. Nat. Hist. XXIII, 1907, 

 pp. 669-807, 5 pis. 31 text-figs. 



sfitudes Myrm§cologiques en 1884, Bull. Soc. Vaud. Sci. Nat. XX, 91, 1884, pp. 1-65, 1 pi. 



<See Pergande, Mexican Formicidse. Proc. Cala. Acad. Nat. Sci. 3 ser. Vol. V, 1895, p. 896. 



