516 THE AMERICAN NATURALIST. [VOL. XXXV. 
C. Various combinations of the regular and irregular types of compound 
nests and mixed colonies. Examples: Solenopsis fugax with Formica 
sanguinea — fusca; Tomognathus — Leptothorax with F. rufa.” 
While this table leaves little to be desired in point of logical 
construction, it is scarcely an adequate expression of the facts 
at the present time. Nor could this be expected, as a decade 
has elapsed since its publication. It seems worth while to 
replace it by a number of coórdinated categories, for two rea- 
sons. First, the case of Leptothorax emersoni, described in the 
first part of this paper, is in certain respects clearly transi- 
tional between Forel's and Wasmann's leading categories of 
compound and mixed nests, so that the dignity of these main 
groups is thereby considerably impaired. Second, the various 
cases, of compound and mixed nests obviously represent several 
independent and more or less divergent lines of phylogenetic 
development, as Wasmann has shown ('91, p. 239). Hence it 
seems advisable to attempt a natural grouping of the cases, 
even at the expense of multiplying categories. I have, there- 
fore, adopted the following headings, which may be cited with 
their equivalents in Wasmann’s table : 
I. P/esiobiosis. Double nests (in Forel’s sense); Was- 
mann’s accidental forms of compound nests. (4 1, 
I and 2.) 
IL. Parabiosis. (Forel '99) Not included in Wasmann's 
table. 
Cleptobiosis. Wasmann’s * Diebsameisen "; first reg- 
ular form of compound nest. (A II, 1.) 
IV. Xenobiosis. Inquilines, or guest ants; Wasmanns 
** Gastameisen "; second regular form of compound 
Amt (ATT, 2) 
e 
pad” 
Lom] 
V. Dulosis. Slavery. (*Esclavagisme," Forel.) Wasmann J 
normal forms of mixed colonies. (BI, 1 and 2.) 
VI. Colacobiosis. Social parasitism (Forel) ; Wasmann's 
third case of normal mixed colonies. (21, 3-) 
VIL Synclerobiosis. Mixed nests of uncertain origin and 
meaning. Wasmann’s last case (B II, 3 ¢) of acci- 
dental (abnormal) mixed colonies. 
