146 THE AMERICAN MUSEUM JOURNAL 
group of their primitive ability to establish colonies exclusively 
through their own initiative. Hence when, during their nuptial 
flight, they drift too far away to find workers of their own 
colony or species at hand to assist them, they are compelled to 
solicit the aid of workers of another species. The extremely com- 
mon, widely distributed, and very cowardly ants of the fusca 
and schaufusst groups are the ones naturally exploited for this 
purpose. In the species of the rufa group with large queens we 
probably still have the earlier phylogenetic stages of this de- 
velopment: the parasitic instinct is highly developed, but the 
stature of the ants has as yet undergone little or no diminution. 
In the species with diminutive queens, however, like F. nepti- 
cula, microgyna and consocians, we have the last stages in this 
retrogressive development, since the inability of the queen to 
establish a colony unaided is manifested not only in her para- 
sitic instincts, but also in her diminutive size and frail structure. 
Second, the queen may not only seek adoption among alien 
workers, but she and her progeny may continue to live with their 
hosts as permanent parasites. This seems to be the case in 
some of the European ants of the genus Strongylognathus and in 
the workerless species of Anergates, Epecus, Epiphetdole and 
Sympheidole. 
Third, the queen may compel her own adoption or may 
snatch away the pup of an alien species and leave to the workers 
that hatch from them the care of bringing up her own offspring. 
These may, in turn, take to robbing the worker pupze from other 
colonies of the host species and in this manner keep up a per- 
manent mixed colony. This is slavery, or “dulosis,” as prac- 
ticed by the sanguinary ants (Formica sanguinea) and the 
amazon ants (Polyergus rufescens) of Europe and their American 
subspecies and varieties. 
Experiments on artificial colonies of F. sanguinea subsp. 
rubicunda Emery have given an insight into the method in all 
probability adopted by this insect while founding its colonies 
under natural conditions. A detailed account of these experi- 
ments will be published in the near future, but the results may 
be here briefly stated. When a female rubicunda from which 
the wings have been removed is confined in an artificial nest 
