ANTS AND THEIR COLONIES 145 
species. The latter method of colony formation appears under 
three aspects: 
First, the queen may seek adoption in a moribund or queen- 
less colony of another species and there have her young fed and 
reared by the alien workers. Later these die off and leave a 
pure colony of the parasitic species, which has now waxed 
sufficiently strong and independent, both in number and pugna- 
city, to hold its own in the struggle for existence. In the former 
note in the JOURNAL attention was first called to this type of 
temporary social parasitism in a Connecticut ant (Formica 
difficilis var. consocians) which, till its colony is established, 
lives with the common F. schaufusst var. incerta. During the 
past July the author was able to confirm and extend his ob- 
servations on these insects. It was learned that queens of F. 
consocians were readily adopted by zncerta workers, even when 
the latter had been isolated as pupz and could not, therefore, 
have had any previous experience with the parasites. It was 
also discovered that workers of our common black ant (For- 
mica fusca var. subsericea) could be induced to adopt solitary 
queens of the mound-building ant (fF. exsectoides) and the fallow 
ant (Formica rufa subsp. integra). Hence it is probable that 
these species, which, of all our ants, develop the largest and most 
formidable colonies, start as humble temporary parasites in the 
nests of another species. Very recently Wasmann has shown 
that the author’s conclusions are in all probability applicable 
also to the European ants of the rufa and exsecta groups. 
The parasitic instincts of the queen ants belonging to the 
rufa and exsecta groups, which include F. consocians, integra, 
exsectoides and all the different forms of fallow ant (F. rufa) 
both of Europe and America, are probably traceable to a pecu- 
liarity of the adult colonies of these insects. It is known that 
these colonies sometimes consist of dozens of different nests, 
which have all been founded by young fertilized queens, ac- 
companied by a number of workers of their own species, as 
offshoots from the original nest, that is, the one first established 
through temporary social parasitism. This habit of propa- 
gating a colony over several nests often many feet apart, has 
probably been the means of depriving the queens of the ruja 
