The Ants of the Baltic Amber. 
19 
amber species of (Ecophylla are somewhat more primitive and more 
closely related to Gesomyrmex and Dimorphomyrmex than is the recent 
(E. smaragdina of the Old World tropics. The genera Protaneuretus 
and Paraneuretus are certainly archaic types and related to the single 
existing species of Aneuretus (A. simoni Emery) of Ceylon, whieh is 
justly regarded as a connecting link between the subfamilies Ponerince 
and Dolichoderince. Apart from these and possibly a few other 
exceptions, however, the amber ants are as highly specialized as 
existing forms and one would not be surprised to find living species 
of any of the extinct genera turning up in certain little explored 
portions of the Old World tropics, just as a living species of Geso- 
myrmex was found in Borneo years after this genus had been disco- 
vered in the amber. 
Not only is the generic and specific habitus of the amber ants 
very highly specialized, but their various castes or phases are as sharply 
differentiated and in precisely the same manner as in our recent forms. 
Although all this could be readily inferred from Mayr’s work of 1868, 
we find an extraordinary statement by a geologist of high repute, 
Joseph Leconte, in his well-known „Elements of Geology u published 
in 1884. Misled by the fact that nearly all the Miocene ants preserved 
in the lacustrine formations of Florissant, Oeningen and Radoboj are 
males and females, he says: ,,It is probable that ants at first were 
only winged males and females living in the open air like other in- 
sects. The wingless condition and the neutral condition are both 
connected with their peculiar social habits and instincts, and have 
been gradually developed along with the development of their habits 
and instincts. It is probable that all these remarkable peculiarities, viz. 
the wingless condition, the neutral condition, the wonderful instincts, 
and organized social habits, have been developed together since the 
Miocene Ep och.“ So far is the latter portion of this statement 
from being true that we may confidently assert that the differentiation 
of the worker caste among these insects must have been completed 
before the beginning of the Tertiary and therefore not later than the 
Cretaceous or even the Jurassic or Triassic periods. 
In two of my former publications *) I stated that I was unable 
to detect any evidence that the ants of the Baltic amber had developed 
any dimorphism or polymorphism within the limits of the worker caste 
!) Comparative Ethology of the European aud North American Ants. Journ. 
Psychol. u. Neurol. XIII, 1903, pp. 404—435, 4 pls. and 6 text-figs; and Ants, their 
Structure, Development and Behavior, Columbia University Press, 1910, p. 174. 
2 * 
