No. 415.] NESTS OF AMERICAN ANTS. 515 
6. The dominant species is represented by $ 9 ğ and their 
developmental stages, the auxiliaries by the workers and 
their developmental stages and by fertilized females. Colo- 
nies arising by affiliation ipia ick Strongylogna- 
thus testaceus — Tetramorium cespitum 
c. The dominant species appears to be represented only by the 
and its developmental stages, the barra by ¢ 9 
and their developmental forms.! y predatory colo- 
nies, which, however, do not arise M the above through 
the robbing of the pupa of strange nests, but by the domi- 
nant species driving out the latter and taking possession 
both of their nest and brood. TZomognathus sublevis > 
Leptothorax acervorum or muscorum. 
3. The dominant species has no worker form : Anergates atratulus 
& 9 and their developmental stages > Tetramorium cespt- 
tum D only). Perhaps these colonies might be more 
conveniently designated as guest colonies. 
II. Accidental (Abnormal) Forms : 
1. Artificial mixed colonies arising through affiliation. Examples : 
Formica sanguinea > pratensis; F. rufa = pratensis ; Poly- 
ergus rufescens — rufa 
2. Artificial mixed colonies of predatory origin : 
a. Produced in confinement: F. sanguinea ~ workers of fusca 
or rufibarbis (normal auxiliaries) ; rufa, pratensis, cinerea, 
exsecta, pressilabris (abnormal auxiliaries). 
6. Occurring in a state of nature: F. sanguinea — workers of 
fusca and pratensis or rufibarbis and pratensis. 
3. Natural, abnormal, mixed colonies : 
a. Unusual auxiliaries, with the usual dominant species. Preda- 
tory colonies : 
pues: sanguinea — workers of pratensis. 
e « « e rufa. 
a e « z * rufa and fusca. 
^. Usual auxiliaries, with an unusual dominant species. Colo- 
nies probably arising by affiliation: 7. pratensis — fusca, 
truncicola — fusca, exsecta œ fusca. 
c. Neither species living, as a rule, with other ants, either as 
auxiliaries or as dominant species : Tapinoma erraticum = 
Bothriomyrmex meridionalis. 
! This assertion now requires modification, since Adlerz has published his later 
6). 
observations (’9 
