Page:Phylogeny of cynipid genera and biological characteristics.pdf/22

 At any rate, I see no warrant for believing that the origin of the agamic condition in dimorphic species of Cynipidæ has any connection with the origin of the agamy in species, like Rhodites sp., which do not have an alternation of generations. If it is true that there are no such evolutionary relationships, then we may believe that the agamic condition arose independently at four different times within the family: at three points discussed in the preceding section of this paper, and in the connection in which we have discussed it here.

To summarize our conclusions concerning the origin of heterogeny among the Cynipidæ, it is suggested that the alternation of different forms of galls and of adults arose gradually, after a struggle for the fixation of the habits of each generation, among the wasps of the genus Neuroterus (or among allied groups), due primarily to seasonal, environmental conditions; that this alternation of generations is merely a more or less extreme type of seasonal dimorphism; and that the occurrence of agamy in one generation is mainly a result of seasonal exigencies.