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WHEELER. 



[VOL. II. 



supported by many valuable observations on the hive-bee. 

 Now, while we can, perhaps, understand how these more spe- 

 cialized ants may manage to control the quantity and quality of 

 liquid food regurgitated from their own crops and salivary 

 glands, it is not so easy to understand how ants can exercise 

 such control when they adopt a capricious method of feeding 

 like that of the Ponerinae. Such a method can hardly produce 

 clear-cut results ; i.e., either workers or fertile females. And 

 a comparative study of the better known species of Ponerinae 

 shows that in certain species at least there is no such sharp 

 distinction between the sterile and fertile female as we find in 

 the more specialized ants. Not only is the female sex in a 

 state of morphological and physiological instability, i.e., di- or 

 even tri-morphic, but the male sex also is sometimes dimorphic 

 - at least in the same genus, if not in the same species. For 

 the purpose of illustrating this singular instability of the sexes 

 I have compiled the following table from the literature to which 

 I have access. 1 It includes twelve of the better known species 



1 Sharp, " Formicidae in Cambridge Natural History," Insects, vol. vi ; Emery, 

 " Sopra Alcune Formiche della Fauna Mediterranea," R. Accad. delle Scienze 

 deir htituto di Bologna, 21 Apr., 1895; Emery, " Beitrage zur Kenntniss der 

 nordamerikanischen Ameisenfauna," Schluss, Zool.Jahrb., Abth. f. Syst, Bd. viii. 



