96 Psyche [June 



the cedar brakes and post-oak woods of central Texas. Both are 

 essentially lowland species. T. arizonensis, however, lives in the 

 arid, stony mountain canyons of southern Arizona and undoubt- 

 edly also in similar localities in northern Mexico. In the Hua- 

 chucas the nests were never seen on ridges or elevations but 

 invariably on the slopes or in the very beds of the small dry 

 arroyos entering from the north the main canyons which run 

 from west to east. These situations are evidently selected 

 because of their greater exposure to the southern sun and the 

 longer retention of moisture in their soil. 



The nests can be easily recognized by the portions of ex- 

 hausted fungus gardens scattered about their main entrances. 

 This refuse is usually of a bright yellow color and quickly arrests 

 the eye of one who is scrutinizing the soil for signs of ants. The 

 largest arizonensis nest seen was situated in front of Mr. Joseph 

 Palmerlee's ranch in Miller Canyon at an altitude of 5500 ft. It 

 was in such hard, stony soil that I was unable to reach its lower- 

 most galleries even when Mr. Palmerlee came to my assistance 

 with a large pick and a pair of powerful arms. The nest had three 

 entrances, one on a rude crater sprinkled with yellow fungus- 

 garden refuse and two others about 10-14 inches from the crater 

 opening and about a foot apart at the edge of a boulder some three 

 feet in diameter. On removing this the two openings were seen to 

 lead into converging galleries ^ to f of an inch in diameter, which 

 ran along the surface of the soil for several inches, and then united 

 and descended perpendicularly as an irregular passage-way be- 

 tween a couple of large stones to a depth of two feet. Here it 

 joined an obliquely ascending gallery which was traced to the 

 opening on the crater, and the common gallery thus formed at 

 once opened into a chamber 10 inches long by 6 inches in diameter 

 and only 2-3 inches high, the roof of which was formed by the 

 lower surface of one of the two large stones. Although this 

 chamber was apparently a natural cavity and had not been exca- 

 vated by the ants, it nevertheless contained a large fungus-garden 

 which was suspended from the lower surface of the stone and hung 

 in folds like a series of curtains. In this respect and also in its 

 bluish white color it resembled very closely the gardens of T. 

 seyientrionalis and jamaicensis which I described in my former 

 paper (loco citato pp. 750 and 760). From the floor of the chamber 



