THE TEMPORARY SOCIAL PARASITES. 439 



This dependent stage, which, as I have said, is of much greater 

 duration than the independent stage in the long life of the queen, leads 

 to a number of phylogenetic developments of the defective type. 

 These first manifest themselves in the adoption of young queens 

 by adult workers of their own species. A word of explanation will 

 make this clear. In the colonies of many species of Formicidse we 

 find several queens in fact, there are comparatively few ants whose 

 adult colonies do not contain more than one of these fertile individuals. 

 And a study of the growth of such colonies shows that the super- 

 numerary queens are either daughters of the original single queen that 

 founded the colony, or have been adopted from other colonies of the 

 same species. Hence these queens are either virgins, or have been 

 impregnated by their own brothers ( adelphogamy of Forel ) in the 

 parental nest, or have been captured by the workers and carried into 

 the nest after descending from their nuptial flight. This passive or 

 forcible adoption leads necessarily to a complete suppression of the 

 independent stage in the life of such queens. I have found that merely 

 removing a queen ant's wings with tweezers will at once call forth the 

 dependent series of instincts, and the same result is undoubtedly pro- 

 duced when the workers dealate the virgin or just- fertilized queens 

 of their own or other formicaries. Such queens, finding themselves 

 surrounded by a number of accomplished nurses, the workers, proceed 

 at once to act like old queens that have already established their 

 colonies and brought up a brood. 



From this condition of facultative adoption to an obligatory adop- 

 tion of the queen by workers of her own species is but a step. And 

 here there are three possibilities : first, the queen can establish a colony 

 only with the aid of workers of her own species and of the same colony. 

 This condition seems not to obtain among ants, although it is well 

 known in the honey-bees. Second, the queen must either be adopted 

 by the workers of her own species of the same or another colony or by 

 workers of an alien species. This is the case with many queen ants 

 that have lost the power of establishing colonies unaided. Third, the 

 queen must always be adopted by an alien species. This is the case in 

 the highly parasitic forms that have lost their worker caste. The three 

 conditions here enumerated clearly represent the transition from para- 

 sitism of the queen on the same to parasitism on an alien species. The 

 latter alone is commonly regarded as true parasitism, but the former, 

 which, of course, can occur only among social organisms or during 

 social stages in the lives of solitary organisms, is parasitism in every 

 essential particular. 



Ant colonies are such closed and exclusive societies that the adop- 



