Dec, ipii.] Wheeler: Fungus-Growing Ants from Texas. 245 



DESCRIPTIONS OF SOME NEW FUNGUS-GROWING 



ANTS FROM TEXAS, WITH MR. C. G. HARTMAN'S 



OBSERVATIONS ON THEIR HABITS.' 



By William Morton Wheeler, 

 Boston, Mass. 



(With Plate VIII.) 



During the past summer, Mr. Carl G. Hartman, of Huntsville, 

 Texas, sent me a number of fungus-growing ants whose habits he 

 had been carefully observing. I at first regarded the specimens as 

 representatives of an undescribed species of the subgenus Trachy- 

 niyrmex (genus Atta) but on comparing them with a large amount 

 of material from various portions of Texas and of the United States 

 east of the Mississippi River, I find that they represent a couple of 

 undescribed varieties of T. scptentrionalis MacCook. This compari- 

 son also shows that this species is far from being as uniform in its 

 characters as has been hitherto supposed. In my paper on our fungus- 

 growing ants* I did, indeed, distinguish a darker southern form of 

 septentrionalis from Texas and Florida as distinct from a paler form 

 occurring in New Jersey and the District of Columbia, and regarded 

 the latter as the type of the species. The former was designated as 

 var. ohscnrior. My description of the three phases of the species, 

 however, was drawn from Texas specimens. Renewed study of the 

 materials in my collection together with numerous specimens from 

 several colonies received from Mr. Hartman, leads me to regard 

 ohscnrior as a subspecies, which presents several distinct varieties. 

 I have also found an interesting color variety of the typical scptentrio- 

 nalis. The workers and females of these different forms may be de- 

 scribed as follows. 

 I. Atta (Trachymyrmex) septentrionalis MacCook (typical). 



Worker. — Length 3-3.5 mm. 



Gaster rather globose, with convex sides and faint lateral ridge on the first 

 segment. Surface of body rather smooth, slightly shining ; tubercles small and 



' Contributions from the Entomological Laboratory of the Bussey Institu- 

 tion, Harvard University, No. 50. 



^ The Fungus-growing Ants of North America," Bull. Amer. Mus. Nat. 

 Hist., XXIII, 1907, pp. 669-807, 5 pis., 31 text figs. 



