DEVELOPMENT OF SEX IN SOCIAL INSECTS. 87 



in two directions, and finally led to the establishment of two perfectly 

 distinct forms of female," the Professor says, and yet after determining 

 in his own mind that selection (we are not told what selection, or how 

 it acts) has " led to the establishment of two perfectly distinct 

 forms of female," the Professor goes on to state : — " That the 

 process has not been sudden, but has been brought about step by step, 

 is apparent ; for even at the present day a number of stages in these 

 metamorphoses are still to be found among the workers of the diflt'erent 

 species of ants. Moreover, sporadic transition-forms between workers 

 and females also occur, and show varied combinations of character- 

 istics." Yet, in spite of this, the Professor tells us there are " two 

 perfectly distinct forms of females." Does he mean to suggest that 

 morphologically the ovaries of the queens and workers are not one and 

 the same organ in difi'erent degrees of development, between which he 

 states there are transition forms ? If so, I doubt whether anyone will 

 agree with him. If he does think they are the same, and I think he 

 does, for he says that " the degeneration of the ovary has proceeded on 

 its slow phyletic course, step by step, and has caused one egg-tube after 

 another to disappear," how does his theory of two kinds of female-ids 

 explain the origin of the differences which exist in queens and workers ? 

 Is not the theory merely a suggestion of how the differences may be 

 supposed to be transmitted, rather than an explanation of origin ? 

 That the Professor considers the ovaries structurally the same in 

 workers and queens is again evident when he tries to convince his 

 readers that the germ-plasm is really composed of " ids," for he refers 

 to " the gradual metamorphosis of the females into workers among 

 state-forming insects." What, then, does the expression there are 

 " two perfectly distinct forms of females " mean ? I fail entirely to 

 see in what way there can be considered two forms at all. The rest of 

 the learned Professor's arguments are based on the theory that the 

 germ-plasm is actually composed of " ids," and that the " ids " 

 can be again subdivided into the " primary constituents of the different 

 independently varying parts of the body — that is of ' determinants,' " 

 and as he has entirely failed to convince us in his explanation of the 

 presence of these " ids " in the germ-plasm, or in fact of the necessity 

 of the supposition that they are there, it is clear in our opinion 

 that the rest of the conclusions are of no great value. 



It may be well, however, briefly to consider the remaining points 

 of the Professor's arguments with regard to social insects. He assumes 

 that at first only a small group of the "determinants" of the egg 

 varied in the case of ants, possibly those " of the reproductive organs 

 and wings," and on the variation of these determinants in the egg, the 

 female-id became modified into either a worker-id or a queen-id, 

 whilst he still further supposes that in those ants where two forms of 

 workers occur, the worker-id sometimes became modified in the 

 direction of forming soldier-ids. 



By supposing the germ to be made up of a number of " ids," which 

 in their turn are subdivided into " determinants," or primary constituents 

 of the different parts of the body, the Professor explains the phenomena 

 of " polymorphism" by the suggestion that it is in all cases a variation 

 of the determinants of those parts which have to adapt themselves to 

 new demands of the conditions of life, and hence that the development 

 of any of these variable determinants would produce an altered form. 



