56 THE ARGENTINE ANt. 



Many permanent nests are located in the tops of trees, in rotten 

 branches, or m phxces where borers or termites have been working:. 



In rotten logs the ants will nearly always utilize old borer or termite 

 tunnels for their nests, but do not appear to do any boring for them- 

 selves. 



The facility with which entire colonies move is sometimes amazing. 

 If a nest is disturl)ed the workers will frequently move all stages and 

 establish another nest in a fresh location in the course of a very few 

 mini lies. 



UNDERGROUND NESTS. 



The ants seldom bin-row to any great depth in the ground. The 

 exceptions to tliis occur durmg hot, dry weather in the summer or 

 during particularly cold spells in the winter. In the dry spells they 

 CAddently work downward in an endeavor to secure suflicient hu- 

 midity for the young, while in the wintertime they sometunes go 

 deep into the soil for the sake of protection from the cold. The 

 deepest burrows which we have measured have been 14 inches in 

 depth, but they usually average from 4 to 10 inches imder normal 

 conditions. These deep burrows are usually located at the foot of 

 tree trunks, or under the ridges in cane, cotton, or corn fields. 



Under more favorable circumstances, however, the underground 

 galleries average from 1 to 4 inclies in depth. In summer time the 

 ants appear to do as little excavating as possible and seem to limit 

 their efforts to excluding light and water. When the nests are 

 located above ground, under boxes, boards, stones, etc., very little 

 soil is used, and this is utilized in closing holes, etc., to keep out 

 light and drafts. 



WET-WEATHER NESTS OR SHEDS. 



In wet situations or after heavy rains, when the ground has become 

 soaked with water, the ants construct curious honeycombed structures 

 around the bases of tree trunks. These arc made of a great number 

 of fine, loose particles of soil, usually supported by grass stems or 

 loose leaves. They vary from one-half inch to as much as 5 inches 

 in height, and sometimes cover an area of several square feet. They 

 are built with great rapidity by the workers, and are extremely frail, 

 falling in at the lightest touch. As a result of this weakness these 

 nests disa])pear after a few days of dry weather, or are washed away 

 by showers. They consist of a maze of covered galleries, in which 

 large numbers of the larvae and pupse are placed. Their purpose 

 appears to be to afford protection to the young stages until the 

 ground gets dry enough for the underground galleries to be 

 reoccupied, or they may be used to dry and "air" stages which 

 have become wet, the loose construction permitting a liberal circula- 

 tion of the air through the walls and ceilings. (See PI. V.) 



