774 



SCIENCE. 



[N. S. Vol. XV. No. 385. 



have been able to capture the entire 

 colonies, I have found in each case only a 

 single soldier. This individual is of extra- 

 ordinary aspect, its huge, cylindrical head 

 being unlike that of any known species of 

 Pheidole. In none of the nests have I been 

 able to find a queen. As the abdomen of 

 the single soldier is relatively larger than 

 in other species of the genus, it is possible 

 that this singular individual may produce 

 eggs and thus replace the winged queen 

 as the mother of the colony. The colonies 

 of Ph. lamia certainly present a miserable 

 appearance when compared with the teem- 

 ing colonies of other species, and it is diffi- 

 cult to avoid the conclusion that the small 

 size of the colony, the suppression of all 

 but a single soldier. and the possible elimi- 

 nation of the queens, are the result of un- 

 favorable conditions. This ant is, I believe, 

 really an effete or evanescent species, a 

 species in what Hyatt called the phylo- 

 gerontic stage. 



Although many additional observations 

 both of species of Pheidole and of other 

 genera could be given, I believe that 

 enough evidence has been presented to 

 show that ants normally live under condi- 

 tions eminently favorable to the production 

 of variations and the preservation of these 

 in the sexual forms till the latter are able 

 to meet the exigencies of the struggle for 

 existence ^vith the best endowment of vigor 

 and nutrition. We should therefore expect 

 the ants to display a high degree of 

 variability, and this is fully borne out by 

 a study of these insects as a family in the 

 taxonomie sense. Up to the present time 

 the ants alone of all invertebrate animals 

 have been successfully treated in taxonomy 

 like the birds and mammals. The tri- 

 nomial and quadrinomial nomenclature in 

 the hands of Professors Emery and Porel 

 admirably expresses the fine shades and 

 relative stability of the form and color 

 variations which can be recognized in these 



insects. It is safe to predict that a quin- 

 quenomial system may be necessary before 

 long adequately to symbolize the still more 

 delicate subvarietal deviations observed in 

 different nests of the same varieties. 



The importance of this high variability 

 or plasticity from the standpoint of the 

 development of instincts and intelligence, 

 and in fact in all those life-activities which 

 may be conveniently designated as etho- 

 logical* must be apparent on a moment's 

 reflection. In my opinion the manifold 

 and often wonderfully perfect morpho- 

 logical and psychological adaptations, 

 which have made the ants the dominant 

 group among terrestrial invertebrates, have 

 their origin in the variability so greatly 

 enhanced by the production of enormous 

 numbers of individuals and the care and 

 protection afforded, through a most im- 

 portant period of their lives, to the repro- 

 ductive individuals of the colony. This is 

 true no matter what views we may hold on 

 the subject of selection since, so far as the 

 substance of this paper is concerned, it 

 may be immaterial whether we demand 

 that there shall be many simultaneous 

 variations of the same kind, that the 

 variations shall be saltatory, gradual, de- 

 terminate or indeterminate, whether we 

 pin our faith to 'orthogenesis' or to Dar- 

 winism in its original form, to coincident 

 (' organic ') or to germinal variation. Any 

 or all of these forms of variation may 

 exist in the fully developed ant colony and, 

 in all probability, also during the great 

 periodic increase in numbers exhibited by 

 many other animals. 



William Morton Wheeler. 



University of Texas, 

 March 19, 1902. 



* In a forthcoming paper I hope to justify 

 the use of this term as it is employed by some 

 French zoologists in the place of the less satis- 

 factory ' ecology,' ' natural history ' and ' Biol- 

 osrie ' in the German sense. 



