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 by 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. Accacl. Sc. 1st. Bologna, 1897. pp. 
147-167, 1 pi. 
1911 Genera Intsectorum. Family 
Formicidae, 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. 
