Preliminary Report on Pterergates in Pogonomyrmex Californicus

The phylogeny of castes among social insects has a recognized importance in the question of development of organic forms through continuous or saltatory variation. For the Formicidae the castes are already well established in the early Tertiary, among the first fossil records of these insects, although in the primitive ancestral wasps neither the social habit nor the polymorphism of the female appears. Differentiation into soldier, worker, and fertile forms is also a long-standing condition with the termites, probably dating from the Cretaceous.