736 



Bulletin American Museum of Naturol History. \yo\. XXIII, 



nest was easily excavated, o^viiig to its location in an exposed bank of pure 

 sand, nevertheless I was made very uncomfortable by the attacks of the 

 soldiers, who actually drew blood with their sharp mandibles. 



An interesting nest was excavated and measured by Messrs, Brues and 

 Melander during the spring of 1903. This was situated on the right bank 

 of Barton Creek (Fig. 10) near Austin, about 15 m. above the bed of the 

 stream. In surface view (Fig. 11) it presented a low, irregular mound, con- 



's a.-n.(i. 



TRiCi 



Fig. 12. Diagram of the Atta texana nest represented in the preceding figure. (From a 

 sketch by Messrs. Brues and Melander.) 



sisting of fused or contiguous craters of pure sand resting on a layer of blue 

 clay. As shown in the diagram. Fig. 12, galleries descended vertically from 

 these craters through the blue clay layer, which was nearly 2 m. thick, and 

 continued down through an equally thick layer of red clay, where they 

 entered a layer of pure sand about a meter in thickness. At the top of this 

 last layer they opened into a number of large chambers communicating with 



