1 66 ANTS. 



viiluals belonging t<> each subfamily can be satisfactorily given only 

 for the ants of the I'.altic amber. Of the 2,158 specimens examined by 

 Mayr and Andre, 704 were Camponotinse, 1,310 Uolichoderime, 59 

 .MyrmiciiKe and 25 I'onerinae. The great preponderance of Dolicho- 

 derin;e is due to two species, Bothriomyrmex yocpperti (889 speci- 

 mens) and lritimn\rmc.\- ^cinitsi (248 specimens), which are repre- 

 sented by 1,137 specimens, or more than half of the total number. The 

 species of Myrmiciiue and Ponerinse are each represented by only a few 

 individuals. From these facts Mayr concludes " that the Ponerinae of the 

 Tertiary exhibited the weakest development and have reached their 

 full eftlorescence in recent times." He advances a similar opinion in 

 regard to the Myrmicinas. Emery, however, has shown that this infer- 

 ence is erroneous, for the Ponerinae and the same is true of the 

 Myrmicime are much less arboreal in their habits than the Dolicho- 

 derinae and Camponotinse, and would therefore be much less fre- 

 quently entrapped in the liquid exudations of succiniferous trees. 

 Then, too, the Ponerinae probably formed small colonies as they do at 

 the present time. I have found several undescribed Ponerinae and 

 Myrmicinae both in the Baltic amber and in the shales of Florissant, 

 showing that these groups must have been at least as highly diversified 

 in the Miocene and lower Oligocene as the other two subfamilies. 



Only in the amber species have the genera been at all satisfactorily 

 established. Those described from other formations are very largely 

 guesswork. This is especially true of such genera as Heer's Imhoffia. 

 Attopsis and Poneropsis. Other species were placed by him and Scncl- 

 der in the recent genera Lasius, Formica, Dolichodems, Camponotus, 

 Mvnnica and Aphccnogaster, but probably many of these allocations 

 are erroneous. The only genera not represented in the amber, but occur- 

 ring in the Tertiary strata, are Lonclwinynnc.r (Fig. 90) and Liometo- 

 pnw. We may divide the genera of the Baltic and Sicilian ambers into 

 two groups, the extinct and recent, and the latter may be subdivided 

 into those still represented by species in Europe (palearctic ), which are 

 nearly all common to the nearctic region as well (circumpolar), and 

 tin KO now confined to the tropics of the Old World (paleotropical). 

 Grouping the genera thus, we have the table on page 167. 



Of the 40 genera included in this table, 13 are extinct and 27, or 

 more than two thirds, are still living. Of the latter, a little more than 

 half (14) are still represented in Europe and a little less than half 

 (13) in the Old World tropics. It will also be seen that the ratio 

 (7:4) of exclusively paleotropical to palearctic genera in the Sicilian 

 amber is nearly twice that of the Baltic amber (11:13), although 

 very few specimens of the former have been examined. But it should 



