54 Annals Entomological Society of America [Vol. I, 



certain localities are gynaecoid workers. In the American Lepto- 

 thorax emersoni, as I have shown (1903), gynsecoid workers and 

 ergatogynes are unusually abundant while the true females seem 

 to be on the verge of disappearing. Among the typical amazon 

 ants (Polyergus rufescens) of Europe, ergatogynes are not uncom- 

 mon. In Strongylognathus testaceus the worker caste seems to 

 be dwindling, while in several permanently parasitic genera 

 (Anergates, Wheeleriella, Epoecus, Epipheidole and Sympheidole) 

 it has completely disappeared. Only one cause can be assigned 

 to these remarkable effects — the abundance of food with which 

 the parasites are provided by their hosts. 



8. In the Ponerinee and certain Myrmicin^, like Pheidole, 

 Pogonom^n^mex and Aphaenogaster, the larv^ are fed on pieces 

 of insects or seeds, the exact assimilative value of which as food 

 can neither be determined nor controlled b}" the nurses. And 

 while the3^may perhaps regulate the quantity of food administered, 

 it is more probable that this must fluctuate within limits so wide 

 and indefinite as to fail altogether to account for the uniform and 

 precise morphological results displayed by the personnel of 

 the various colonies. Moreover, any accurate regulation of the 

 food supply by the workers must be quite impossible in cases like 

 that of the Pachycondyla larva bearing the commensal ]\Ietopina. 



9. The dependence of the different castes of the social insects 

 on the seasons may also be adduced as evidence of the direct 

 effects of the food supply in producing workers and queens. The 

 latter are reared only when the trophic condition of the colony is 

 most favorable and this coincides with the summer months; in 

 the great majority of species only workers and males are produced 

 at other seasons. Here, too, the cause is to be sought in the defic- 

 ient quantity of food rather than in its quality, which is, in all 

 probability, the same throughout the year, especially in such ants 

 as the fungus-growing Attii. 



While these considerations tend to invalidate the supposition 

 that qualitative feeding is responsible for the morphological pecul- 

 iarities of the worker type, they are less equivocal in regard to the 

 morphogenic effects of quantitative feeding. Indeed several of 

 the observations above cited show very clearly that diminution 

 in stature and, in pathological cases, even reversion to the worker 

 form may be the direct eft'ect of under-feeding. To the same cause 

 we may confidently assign several of the atypical phases among 

 ants, such as the micrergates, microgynes, and micraners, just 



