1981] 
Droual & Topoff— Genus Pheidole 
149 
Table 4. Observed army ant raids on colonies of P. desertorum. 
Colony 
Dates of Raids 
Species Raiding 
H-Jnll-1 
8/ 1-8/5 
Neivamyrmex nigrescens 
H-Jnll-2 
7/9 
N. 
nigrescens 
H-Jnl2-1 
8/4, 8/6, 8/8 
N. 
nigrescens 
H-Jnl2-4 
7/4 
N. 
nigrescens 
H-Jnl2-5 
7/2* 
N. 
nigrescens 
H-Jnl3-1 
7/12, 8/ 10* 
N. 
nigrescens 
H-Jnl4-1 
8/5, 8/6, 8/12-8/15 
N. 
nigrescens 
H-Jnl8-1 
7/11, 7/12, 7/16, 
7/25, 7/26, 7/28, 8/1 
N. 
nigrescens 
H-Jnl7-1 
8/18 
N. 
nigrescens 
H-Jn25-1 
8/28 
N. 
nigrescens 
H-Jl 4-1 
8/3, 8 / 5—8 / 7, 8/9 
N. 
nigrescens 
H-Jl 30-2 
8/13 
N. 
nigrescens 
H-Jl 15-1 
7/28 
N. 
texanus 
*Colony not seen afterwards. 
the secondary losses which result from the disorganization which 
follows the defense. If this hypothesis proves to be correct, the 
possibility that the frequent emigrations of these species have 
evolved to serve as part of a defense system against the army ants 
has to be entertained. 
Acknowlegements 
This research was supported by a N.I.M.H. training grant (MH 
15341), a Theodore Roosevelt Memorial Fund Grant, PSY-CUNY 
Grant 13492 and a NSF Grant BNS- 8004565. We thank Dr. G. 
Turkewitz for his statistical advice and Roy R. Snelling for identify- 
ing the Pheidole specimens. 
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Carlson, D. M. and J. B. Gentry. 
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