210 Psyche [October-December 



but it is conceivable that the dichthadiigynes may have arisen 

 from fertile workers like those of Diacamma after complete 

 phylogenetic suppression of the winged queen. The latter sup- 

 position will have to be tested by thorough morphological study 

 of all the available fertile female forms. 



The conditions in Diacamma are suggestive also from an- 

 other point of view. It has long been known that well-fed worker 

 ants may lay eggs, but no one has ever seen a male copulating with 

 a worker, and only Reichenbach, Mrs. Comstock and Crawley 

 have found that eggs laid bj^ workers may develop into workers. 

 All other authors (Miss Fielde, Janet, etc.) maintain that such 

 eggs invariably produce males. In Diacamma geometricum we 

 actually have an ant whose workers copulate with the males and 

 must therefore produce worker as well as male offspring, since 

 there is no morphologically differentiated queen. Further studies 

 of tropical ants in the field will probably compel us to to abandon 

 certain other generalizations which we have reached from a too 

 exclusive study of temperate European and North American 

 species confined in artificial nests. 



Bibliography. 

 1916. Arnold, G. A Monograph of the Formicidse of South 



Africa (Myrmicinse). Ann. South Afric. Mus. 14, 



1916, pp. 159-270, 3 pis. 

 1899. Bingham, C. T. Note on Diacamma, a Ponerine Genus of 



Ants, and of the finding of a female of D. vagans Smith. 



Journ. Bombay Nat. Hist. Soc. 12, 1899, pp. 756, 757. 

 1903. The Fauna of British India including 



Ceylon and Burma. Hymenoptera, Vol. 2. London, 



Taylor & Francis, 1903. 

 1897. Emery, C. Revisione del Genere Diacamma Mayr. 



Rend. Sess. R. Accad. Sc. 1st. Bologna, 1897. pp. 



147-167, 1 pi. 

 1911 — Genera Intsectorum. Family 



Formicidse, Subfamily Ponerinse. Fasc. 118, 1911, pp. 



1-125, 3 pis. 

 1903. Holliday, M. A study of Some Ergatogynic Ants. 



Zool. Jahrb. Abth. Syst. 19, 1903, pp. 293-328, 16 figs. 



