1906.] Wheeler, Founding of Colonies by Queen Ants. 97 



While the incipient dulotic colony is, to all appearances, very 

 similar to that of a temporary parasite like F. consocians, there 

 is an important difference in the comparative ages of the per- 

 sonnel in the two cases: In the incipient dulotic colony the work- 

 ers are all younger than the queen, whereas in the incipient 

 consocians colonies some or all of the workers are older than the 

 queen. In the case of riibictinda, the subsericea workers kidnapped 

 as pupae by the queen are in full vigor and may live for three or 

 four years, thus constituting a most efficient entourage for the 

 education of the firstling rubicimda brood. In the colony of the 

 temporary parasite, on the contrary, the conditions after adoption 

 are less favorable, but there is a compensatory advantage to the species 

 in the comparative ease with which adoption may be effected. The 

 rubicunda queen is bound to retain her large stature, vigor and pug- 

 nacity. She may be conciliatory or indifferent towards the subsericea 

 till she is attacked, but then the fiery temper, so characteristic of her 

 species, asserts itself and she makes short work of the hostile workers. 

 In the above experiments the series of actions of which this massacre 

 is the first, is so constant, precise, and purposeful that it must re- 

 present a perfectly normal episode in the life of the female rubicunda, 

 whenever she is subjected to the proper stimulus in the form of a 

 small colony of hostile subsericea workers with their brood. 



Since my experiments were concluded I have received from Prof. 

 Emery a paper ^ in which he predicts for Polyergus a method of 

 colony formation similar to that observed in my artificial nests of 

 rubicunda. He says: "And what of the parasitic and slave-making 

 ants like Polyergus ? Wasmann has formulated for this species an 

 hypothesis which is not altogether satisfactory. He assumes the 

 formation of the colony by alliance between a female Polyergus and 

 alien workers of Formica fusca or rufibarbis. I would hazard a dif- 

 ferent supposition. Forel's observations seem to show that the in- 

 stincts of the female Polyergus are less degenerate than those of the 

 worker; he has even seen a female aiding a hatching callow to escape 

 from its pupal envelope. Moreover, both Forel and I have seen virgin 

 females taking part in slave-making expeditions. I surmise, therefore, 

 that the female Polyergus, after losing her wings, is able to plunder 

 from some feeble Formica colony one or more worker pupae, which 

 will then give rise to her first auxiliaries." So far as they go, nny ob- 

 servations on P. lucidiis are in accord with this hypothesis. It is cer- 

 tainly remarkable, however, that my queens were never seen to 



* Sur rOrigine des Founniliferes, loc. cit., p. 461. 



[May, igoO.] 



