WHEELER: ANTS OF THE GENUS FORMICA. 381 
which has several of the characters of Proformica, is in general habitus 
more like a true Formica. Emery! and I, however, have independ- 
ently reached the conclusion that this ant is properly a Proformica. 
A study of our North American Formicae shows that F. pallide- 
fulva sens lat. is even more worthy than Proformica of ranking as a 
distinct subgenus, for the male differs from that of the other species 
in much the same manner as does the male of Proformica, while the 
worker in the structure of the thorax and antennae is even further 
removed from the species of the subgenus Formica. I have therefore 
erected a new subgenus, Neoformica, to include F. pallidefulvua and 
its various subspecies and varieties and F. moki Wheeler. The latter 
form is provisionally placed in this group because its male and female 
phases are still unknown.’ 
It is possible, as Emery clearly showed, to separate the various 
species of the subgenus Formica into groups. These are more sharply 
defined in the present paper. The rufa-like species with diminutive 
females I regard as constituting a distinct group (microgyna group), 
although I am unable to find any satisfactory worker characters on 
which to base it. The exsecta group is so sharply defined as scarcely 
to admit of discussion. I have expanded the sanguinea group by 
including in it a number of species with notched clypeus though lack- 
ing the parasitic or slave-making habits of the typical sanguinea. 
These species may have to be placed in a group by themselves when our 
knowledge of their sexual phases is more advanced. The rufa group, 
especially in North America, presents the greatest difficulties in the 
delimitation of species. This was clearly recognized by Emery, who 
would be the first to admit that his treatment of our rufa forms was 
inadequate on account of the insufficient amount of material at his 
disposal. I have endeavored to reduce the confusion by recognizing 
the Eurasian truncicola as a distinct species and by referring to it a 
number of forms (integrotdes, integra, and obscuriventris) which have 
been hitherto regarded as subspecies or varieties of rufa sens. str. 
The habits of all these American forms agree very closely with those 
of the Eurasian truncicola and differ from those of rufa and its sub- 
1 Der wanderzug der Steppen-u. Wiistenameisen von Zentral-Asien nach Siid- 
Europa und Nord-Afrika. Zool. jahrb. Suppl., 1912, 15, p. 95-104. Emery’s state- 
ment refers only to F. lasioides, which in my opinion is merely a subspecies of neoga- 
gates (vide infra). 
2 That the ethological affinities of Proformica and Neoformica with Formica sens. 
str. are extremely close is shown by the fact that such form as P. neogagates and N. 
incerta sometimes function, either alone or in company with F. fusca, as slaves, or 
auxiliaries of F. sanguinea. 
