12 William Morton Wheeler. 



ants. For this purpose we may divide the amber genera into two 

 groups : those which are today represented in Europe and Siberia and 

 those either belonging to the Indomalayan and Australian fauna, or 

 with more or less pronounced affinities to this latter fauna. To the 

 first group belong the following 13 genera, with 44 species : 



Ponera (2) Liometopum (1) 



Monomorium (2) Plagiolepis (6) 



Stenamma (1) Prenolepis (2) 



Aphaenogaster (3) Lasius (5) 



Myrmica (1) Formica (6) 



Leptothorax (5) Camponotus (1) 

 Dolichoderus (9) 



The remaining 30 genera and 48 species may be referred to the second 

 group. Among these, however, there are certain genera, such as 

 Prionomyrmex, Bhytidoponera and some of the species of Iridomyrmex 

 (e. g. /. geinitA), which show decided affinities to existing Australian 

 forms, others (Protaneuretus^ Paraneuretus) which are closely related 

 to the Indian Aneuretus and still others (Vollenhovia, Parameranoplus, 

 Enneamerus, DimorpJiomyrmex, Gesomyrmex, Pseudolasius, Dryomyrmex) 

 and several species of Dolichoderus^ which are more like forms now 

 living in the Malay Archipelago. This last fauna, however, comprises 

 an admixture of Indian and Australian types and in this respect most 

 closely resembles the amber fauna. But the aspect of the latter is 

 peculiar, owing to the absence of the genus Polyrhachis and the very 

 poor development of the genus Camponotus, both genera represented 

 by a great number of species in the Malayan fauna. 



We must, therefore, regard the ant fauna of the Baltic amber as 

 a mixture of what at the present day we are able to recognize as at 

 least four different faunas, the palearctic, the Indian, the Malayan 

 and the Australian, with a little more than ^/g of the genera and 

 nearly ^/g of the species palearctic and the remainder belonging to 

 Indomalayan and Australian types. The proportion of individuals in 

 these different faunas will be seen to differ greatly if we omit the 

 two dominant species, Iridomyrmex goepperti and I. geinitzi, to which 

 belong more than half of all the specimens examined, for the genera 

 represented by the greatest number of remaining specimens are Formica 

 (1336), Lasius (1257) and Prenolepis (684), or a total of 3277 speci- 

 mens of the 4961 left after subtracting the 6717 contributed by 

 /. goepperti and geinitzi. It should also be noted that the single species 

 of Dolichoderus (D. tertiarius) which is most like the living D. quadri- 



