The Ants of the Baltic Araber. 
9 
not in existence during the early Tertiary. We must assume either 
that it was then as now confined to the tropics and immediately 
contiguous subtropical beit or that the eminently terrestrial or even 
hypogseie habits of its species excluded it from the amber. The former 
alternative seems to me to be much the more probable, because I have 
found specimens of recent Dorylince (Anomma) in the Zanzibar copal. 
After this brief account of the subfamilies we may proceed to 
a comparison of the genera of the amber with those of recent ants. 
Of the 43 genera, 19 or 44,1° 0 are extinct and 24 or 55,8 °/ 0 are still 
extant. The extant and extinct genera in the subfamilies Ponerince, 
Myrmicince and Dolichoderince are nearly equal in number, but of the 
Camponotince only 4 are extinct, while 9 have survived to the present 
time. This proportion of extinct to recent genera is not widely diffe- 
rent from that found by Ulmer in his admirable study of a very 
different group of insects, the Trichoptera 1 ), which are represented in 
the amber by 30 (53,5 °/ 0 ) extant and 26 (46,4%) extinct genera. In 
the following list the names of the Formicid genera are followed by 
the number of known amber species in parentheses, and the extant 
genera are grouped according to the distribution of their recent species, 
the extinct genera with indications of their nearest affinities. 
1 . 
2 . 
3. 
4. 
5. 
A. Extant Genera. 
Cosmopolit an: 
Ponera (2) 
Aphcenogaster (3) 
Tropicopolit an : 
Platythyrea (1) 
Euponera (Trachymesopus) (1) 
Paleotrop ical : 
Sima (5) 
Monomorium (2) 
Indomalayan and Australi 
Ectatomma (Ehytidoponera) (1) 
Vollenhovia (2) 
Gesomyrmex (2) 
Circumpolar : 
Stenamma (1) 
Myrmica (1) 
Leptothorax (5) 
Prenolepis (2) 
Camponotus (1) 
Iridomyrmex (5) 
Dolichoderus (Hypoclinea) (9) 
Plagiolepis (6) 
( Ecophylla (2) 
n : 
Dimorphomyrmex (2) 
Pseudolasius (1) 
Liometopum (1) 
Lasius (5) 
Formica (6) 
2 ) Die Trichopteren des baltischen Bernsteins. Beiträge zur Naturkunde Preußens, 
herausgegeb. v. d. physik.-ökonom. Gesell. Königsberg. X, B. G. Teubner, Leipzig und 
Berlin, 1912, 380 pp., 480 text-figs. 
