-'>'> ANTS. 



territory covered by tin- annual migrations of any of the species, to dr- 

 UTmine the lime spent in the bivouacs or in the presumably more per- 

 manent breeding nests, or the precise relations which these nomadic ants 

 bear to their myrmecophiles. Curiously enough, these seem to be more 

 numerous both in species and in individuals than the myrmecophiles of 

 the non-migratory ants of other subfamilies. 



Another problem of more theoretical interest is presented by the 

 dichthadiigynes, which are so unlike typical female ants. To Emery 

 these forms seemed to indicate that the females of ancestral ants were 

 windless and that the alate condition represented a secondary inheri- 

 tance from the male sex within comparatively recent times. He was 

 confirmed in this opinion by his discovery of apterous dichthadiiform 

 females in the very primitive species of Acanthostichus and Paras\scia. 

 There is, however, another possibility, which seems not to have been 

 considered. The occurrence in certain Ponerinae (Leptogenys and 

 probably also in Diacamma and Champ somyrmex ) of gynsecoid work- 

 ers that have supplanted the winged females, suggests that the dichtha- 

 diigynes may also be highly modified gyn?ecoids. It must be admitted 

 that this view is beset with serious difficulties. First, we must suppose, 

 on such a hypothesis, that the gynsecoids are phylogenetically fixed 

 forms of very ancient origin, since in Quietus and Eciton they are 

 quite unlike the existing workers in having only a single joint in the 

 pedicel. Hence they cannot be compared directly with the gynsecoicls 

 of Formica, which are merely workers that usurp the queen's place and 

 function during the ontogenetic development of the colony. Second, 

 Emery has figured in the female Doryhts h drains minute " rudiments 

 of wings " and a conformation of the thoracic sclerites suggestive of 

 the typical winged form. If he has correctly interpreted these various 

 structures we are bound to suppose that the dichthadiigyne is a highly 

 degenerate, alate female and both his hypothesis and the one I have 

 suggested must be abandoned. The females of Eciton and &nictns, 

 however, certainly have a much simpler and more worker-like thorax, 

 and I am by no means certain that Emery has correctly interpreted 

 the conditions in Dorylns. Too few female Dorylinse are known at 

 the present time to enable us to decide this question, which must be left 

 to future students. 



