FOSSIL ANTS. '75 



This is certainly true of some genera, but not of Camponotus, to judge 

 from our modern species. The fact remains that no polymorphic 

 workers have been seen in the amber, that the great majority of the 

 species certainly had only monomorphic \vorkers, and that genera like 

 Pheidolc and Phcidologcton, so prominent in the Old World tropics 

 to-day, are conspicuous by their absence. In the Pleistocene, however, 

 genera like Pheidolc and Anouuna have their worker polymorphism 

 fully developed, as I have observed in the Zanzibar copal, so that this 

 condition must have made its appearance during the late, if I am right 

 in concluding that it was absent during the early Tertiary. 



