514 THE AMERICAN NATURALIST. [Vor. XXXV. 
* 4. Compound Nests (susammengesetzte Nester). The consociating 
ants maintain independent households, or ménages ; i.e. constitute separate 
colonies. This form of symbiosis occurs between ants belonging either to 
the same or to different subfamilies. 
I. Accidental (z.e. Occasional) Forms : 
1. Nests established in close proximity to each other by ants which 
have certain predatory proclivities. Examples: TZeframo- 
rium cespitum with Formica sanguinea; Dorymyrmex 
pyramicus with Pogonomyrmex barbatus. 
2. Nests established in close proximity to each other, with the sub- 
sidiary object of securing comfortable, warm, and secure 
quarters. Examples: Formica fusca and Myrmica ruginodis 
with F. rufa and pratensis ; Leptothorax muscorum under the 
bark of pine trunks surrounded by rufa nests; Myrmecina 
latreillei Latr. with F. rufa and exsecta. 
II. Regular Forms : 
1. Thief ants : Solenopsis fugax and Solenopsis orbula with ants 
of much greater size. 
2. Guest ants: Formicoxenus nitidulus with Formica rufa and 
pratensis ; Xenomyrmex stollii with Camponotus abscisus. 
B. Mixed Colonies (gemischte Kolonien). The different consociating 
ants carry on a single household, thus constituting a single colony. This 
form of symbiosis occurs only between ants belonging to the same sub- 
family. 
I. Normal (Ze., Regular) Forms : 
1. The dominant species has its own workers, with toothed man- 
dibles. Colonies clearly of predatory origin. Formica san- 
guinea à Q $ and their developmental forms ~ 1 workers and 
worker pupe of F. fusca or rufibarbis or both, or of F. schau- 
Jussi or fusca (in North America). 
2. The dominant species has its own peculiar workers without 
toothed mandibles. 
4. The dominant species is represented by ¢ 9 $ and their 
developmental stages, the auxiliaries only by the workers 
and their pupz. Predatory colonies : 
a. € clearly predatory in origin: Polyergus rufescens 
F. fusca or rufibarbis (or very rarely both), Polyer- 
gus lucidus œ F. schaufussi. 
B: Colonies probably of predatory origin : Strongylognathus 
huberi — Tetramorium cespitum. 
1 The sign — is used to express the union of two species to form a , single 
colony. The name of the auxiliary (slave) species is always placed after the sign- 
