Dec, I9II.] Wheeler: Fungus-Growing Ants from Texas. -'^l 



either from each other or from the typical obscurior. The observa- 

 tions are, nevertheless, well worth publishing, both because they were 

 made with care and in a new locality, and because our knowledge of 

 the North American Attii is still fragmentary. I am glad, therefore, 

 to append his notes on the general habits of the two varieties and on 

 nine of their nests, which he studied in detail, together with a table of 

 measurements and a plate of figures of their galleries and chambers 

 (Plate VIII). In the figures the chambers are designated by Roman, 

 the galleries by arable numerals. 



" Trachymyrmex obscurior is found in the sandy woods about 

 Huntsville,'on the divide between the Trinity and San Jacinto Rivers 

 at an altitude of about 360 feet above sea-level. The flora of these 

 sandy woods consists of post-oak {Querais minor), black jack (Q. 

 Manlandica), blue jack (Q. brevifolia), hickory {Hkorea viUosa), 

 short-leaf pine {Pinus echinata) , loblolly pine (F. tcrda) , French mul- 

 berry (Callkarpa americana) and bull-nettle (latropha stimulosa). 

 Hymenoptera (Pompihts, Bcmbcx, Sphex, Mutillids, Scoliids, ants, 

 etc.) abound in this locality. Mole burrows are common. Here 

 also occurs another fungus-growing ant, Atta (Mycetosoritis) hart- 

 mani Wheeler, thus far reported only from the sandy floral and 

 faunal island at Montopolis, below Austin, Texas. This island has 

 affinities with the Carolinian region and these affinities are even more 

 apparent in the Huntsville locality, owing to its having a much 

 greater number of eastern species of plants and animals. 



"I have seen T. obscurior only in sandy soil, and she does not 

 burrow into the underlying clay. When the sand is shallow, the 

 chambers of the nest will be reduced in number and increased in 

 size (nests i and 2) and crowded close together by a shortening of 

 the connecting galleries. 



" May and June are the months most favorable for observing the 

 activities of the ants. At this season all the chambers, including the 

 uppermost one, contain flourishing, pendent fungus-gardens. The 

 soil is moist near the surface, but later, as it dries out, the upper 

 chambers are abandoned and the ants retreat to the lower chambers 

 which lie in soil that is probably moist throughout the year. As late 

 as August 29 I found an excellent fungus-garden (but not containing 

 pupae) at a depth of 12 inches. The shade of the trees prevents 

 the heating of the ground to a very great depth. 



