igoS] The Polymorphism of Ants 41 



female, or queen, l^ut in many cases also two distinct castes of 

 workers known as the worker proper and the soldier. 



Different authors have framed very different conceptions of 

 the phylogenetic beginnings of social life among the Hymenoptera 

 and consequently also of the phylogenetic origin and development 

 of polymorphism. Thus Herbert Spencer (1893) evidently con- 

 ceived the colony as having risen from a consociation of adult 

 individuals and although he unfortunately selected a parasitic 

 ant, the amazon (Polyergus rufescens), on which to hang his 

 hypothesis, there are a few facts w^hich seem at first sight, to 

 make his view applicable to other social Hymenoptera. Fabre 

 (1894) once found some hundreds of specimens of a solitary wasp 

 (Ammophila hirsuta) huddled together under a stone on the 

 summit of Mt. Ventoux in the Provence at an altitude of about 

 5,500 feet, and Forel (1874) found more than fifty dealated fe- 

 males of Formica rufa under similar conditions on the Simplon. 

 I have myself seen collections of a large red and yellow^ Ichneuirion 

 under stones on Pike's Peak at an altitude of more than 13,000 

 feet, and a mass of about seventy dealated females of Formica 

 gnava apparently hibernating after the nuptial flight under a 

 stone near Austin, Texas. I am convinced, however, that such 

 congregations are either entirely fortuitous, especially where the 

 insects of one species are very abundant and there are few avail- 

 able stones, or that they are, as in the case of F. rufa and gnava, 

 merely a manifestation of highly developed social proclivities 

 and not of such proclivities in process of development. 



A very different view from that of Spencer is adopted by 

 most authors, who regard the insect society as having arisen, not 

 from a chance concourse of adult individuals but from a natural 

 affiliation of mother and offspring. This view, which has been 

 elaborated by Marshall (1889) among others, presents many ad- 

 vantages over that of Spencer, not the least of which is its agree- 

 ment with wliat actually occurs in the founding of the existing 

 colonies of wasps, bumble-bees and ants. These colonies pass 

 through an ontogenetic stage which has all the appearance of 

 repeating the conditions under which colonial life first made its 

 appearance in the phylogenetic history of the species — the soli- 

 tary mother insect rearing and affiliating her offspring under con- 

 ditions that would seem to arise naturally from the breeding 

 habits of the nonsocial Hymenoptera. The exceptional meth- 

 ods of colony formation seen in the swarming of the honey bee 



