The Ants of the Baltic Amber. l\ \ 



D.janeti and Q. chaperi, would, on this supposition represent relicts 

 of this evolutionary process, which are today leading a precarious 

 existence in the islands of the Malay Archipelago. 



These considerations will explain why I cannot regard the se- 

 paration by Emery of the existing Dvnorphomyrmex in a tribe distinct 

 from the (EcophijlUni, as satisfactory, for this genus is evidently 

 closely related to Oesomyrmex as shown by G. annectens and this 

 latter genus is generally recognized as closely related to (Ecophylla. 

 The separation was made by Emery solely on the structure of the 

 gizzard, but this single character, though important, can hardly be 

 made to outweigh the numerous external resemblances between these 

 three genera and the fact that they merge into one another so in- 

 timately. 



Besides the two amber species described above, a third extinct 

 species has been referred by Emery to the genus Gesomyrmex. This 

 is G. corniger of the Sicilian amber, which is of upper Miocene age. 

 A study of Emery's figures and description of this form, however, 

 fail to convince me that it really belongs to Mayr's genus, although 

 it is evidently an allied form. The shape of the head and thorax, 

 which are both armed with long spines, the position and shape of 

 the eyes and the dentition of the mandibles are so peculiar that in 

 my opinion it should be regarded as the type of a new genus, for 

 which I suggest the name Sicelomyrmex, This ant is evidently a 

 much more highly specialized and geologically more recent form than 

 G. hoemesi and suggests that the group of Camponotince with 8-joint- 

 ed antennae in the worker phase may have reached its highest develop- 

 ment in the Miocene of Europe before becoming extinct on that 

 continent. At the present time this group is represented merely by 

 G. chaperi and B. janeti in Borneo and Sumatra and by two species 

 of Aphomomyrmex {A. andrei Emery and A. hewitti Wheeler) in the 

 former island. 



Genus Prodimorphomyrmex, gen. nov. 

 Worker. Related to Dimorphomyrmex. Head large, flattened, 

 longer than broad, broader behind than in front, with straight sides 

 and broadly excised posterior border. Eyes large, oval, but not reni- 

 form, narrower in front than behind, smaller than in Dimorphomynncx^ 

 less than V3 as long as the head, placed at the middle of its longi- 

 tudinal diameter. Ocelli present, minute. Clypeus small, flat, its 

 anterior border entire, broadly rounded, not projecting. Frontal 

 carinse distinct, widely separated, straight, diverging behind and ex- 



