THE 
AMERICAN NATURALIST 
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Vor. XXXV. October, 190r. No. 418. 
T : THE COMPOUND AND MIXED NESTS OF 
E AMERICAN ANTS. 
WILLIAM MORTON WHEELER. 
Part III. SymMBIOGENESIS AND  PSYCHOGENESIS. 
“Eine Psychologie in Spencer-Darwin'schem Sinne auf Entwicklungslehre 
gegründet, aber auf positiver Detailforschung fussend, verspricht reichere Resul- 
tate als alle bisherigen Speculationen." — E. MACH. 
ALL writers on the behavior of ants have been deeply 
impressed with the cases of social symbiosis, more especially 
with those of an extreme type like Polyergus and Anergates. 
The deadly animosity of the members of a formicary, not only 
towards ants of another species but even towards ants of the 
. Same species belonging to different colonies, is so striking and 
...80 nearly universal that an extraordinary explanation seems to 
. be demanded to account for the cases of amicable consociation 
_ of two species. In the presence of such phenomena, instinct 
and consentience, or sense-experience, have been abandoned 
as inadequate, and the existence in ants of some higher form 
of intelligence, like understanding and ratiocination, has been 
. postulated without further ado. At the same time the evo- 
 lutionist has been stimulated to broach a phylogeny of social 
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