2 
Psyche 
[Mar. 
in g brood. The brood, when mature, comprises a few workers of 
the smallest form of the species. The workers and the adult 
female continue to forage in common until the colony is well 
developed. 
This pattern of colony foundation suggests rather forcefully 
the nature of social organization of the earliest semi-social ants, 
which must long since have become extinct, and suggests fur- 
ther that the development of the social habit in the Formicidae, 
while strikingly similar to that well understood among the 
social wasps and bees and attested in those groups by the exist- 
ence today of contemporaneous living intermediate forms, 
occurred independently in evolution, and probably at a much 
more remote period of time. It contrasts very strongly with the 
evidently derived pattern of claustral colony foundation which 
is common among the higher ants, in which the sexual female 
and the workers commonly differ greatly in stature, and in 
which a complicated physiological mechanism has been devel- 
oped leading to the deterioration of the wing musculature 
shortly after dealation and, probably, to the conversion of this 
bulky protein reserve to a suitable form to assist in the sus- 
tenance of the queen, and to provide food reserves for the devel- 
oping brood. These females, which are typical in such well- 
known genera as Lasius and Camponotus , after flight and deala- 
tion commonly isolate themselves in closed cells, from whicli 
they never emerge to forage. Eggs are laid, larvae are reared 
on a diet consisting entirely of ingluvial food administered by 
mouth, and at maturity the young workers, and they alone, 
break open the cell, emerge to forage, and bring back provender 
to restore the depleted fat-body of the sedentary queen, which 
never emerges into the open air again, except occasionally very 
briefly under unusual circumstances connected with a shift of 
the nesting site. 
This specialized method of colony foundation common to so 
many Myrmicine and Formicine ants presents obvious selec- 
tional advantages over the primitive pattern as exemplified in 
Myrmecia. The young founding female, being amply supplied 
with reserve food material, is far less at the mercy of seasonal 
and environmental hazards than is the female of Myrmecia. 
The female of Myrmecia , forced to forage in the open every 
day or two for nectar or for living prey, is constantly exposed 
