1908] The Polymorphism of Ants 67 



fore be called ergatotelic. The suppression of the primary in- 

 stincts in the queen honey-bee was undoubtedly brought about 

 by a change in the method of colony formation. When the 

 habit of swarming superseded the establishment of colonies by 

 solitary queens, as still practiced by the gynsecotelic insects, the 

 primary instincts of the female lapsed into abeyance or became 

 latent. This change took place so long ago that it has had time 

 to express itself in the structure of the honey-bee as compared 

 with the worker (shorter tongue and wings, feebler sting, degen- 

 erate structure of hind legs, etc.) 



The first of the following examples which seem to indicate 

 the occurrence of instinctive prior to morphological differentia- 

 tion, shows at the same time how the ergatotelic type of the 

 honey-bee may have arisen from the gynsecotelic type of the 

 social wasps and bumble-bees. 



1. The queens of certain species of Formica (F. rufa, exsec- 

 toides, etc.) are no longer able to establish colonies without the 

 cooperation of workers. The common method of colony forma- 

 tion among these insects is by a process of swarming like that of 

 the honey-bee; a certain portion of the colony emigrates and 

 founds a new nest with one or more of the queens. When this 

 method is impracticable the young queen seeks the assistance of 

 an allied species of Formica (F. fusca) , the w^orkers of which are 

 willing to take the place of her own species in rearing her brood. 

 In F. rufa and exsectoides there is nothing in the stature or stnic- 

 ture of the queen to indicate the presence of these parasitic 

 instincts, but, in many of the allied species, like F. ciliata, dakoten- 

 sis, microgyna, etc., the colonies of which are smaller and no 

 longer swarm, or do so only to a very limited extent, the queens 

 have become more dependent on the workers of other species 

 and have developed mimetic characters or a dwarf stature 

 to enable them to enter and exploit the colonies of alien Formicse. 



2. In many ants the callows, or just-hatched workers, con- 

 fine themselves to caring for the larvae and pupse and do not 

 exhibit the foraging instincts till a later period. But even the 

 adult workers may perform a single duty in the colony for long 

 periods of time, if not indefinitely. Thus Lubbock, (1894), and 

 Viehmeyer (1904) have observed in certain Formica colonies that 

 only certain individuals forage for the community. The latter 

 has also noticed that certain individuals, indistinguishable mor- 

 phologically from their sister workers, stand guard at the nest en- 



