1908] The Polymorphism of Ants 51 



while experiments on many organisms have shown that the quan- 

 tity of assimilated food may produce great changes in size and 

 stature, there is practically nothing to show that even very great 

 differences in the quality of the food can bring about morphologi- 

 cal differences of such magnitude as those which separate the 

 queens and workers of many ants. 



These more general considerations are reinforced by the fol- 

 lowing inferences from the known facts of larval feeding: 



1. There seems to be no valid reason for supposing that the 

 morphogeny of the queens among the social Hymenoptera de- 

 pends on a particular diet, since with the possible exception of 

 the honey and stingless bees, to be considered presently, they 

 differ in no essential respect from the corresponding sexual phase 

 of the solitary species. In both cases they are the normal females 

 of the species and bear the same morphological relations to their 

 males quite irrespective of the nature of their larval food. Hence, 

 with the above mentioned exception, the question of the mor- 

 phogenic value of the larval food may be restricted to the 

 worker forms. 



2. Observation shows that although the food administered 

 to the larvge of the various social insects is often very different 

 in its nature, even in closely related species, the structure of the 

 workers may be extremely uniform and exhibit only slight specific 

 differences. Ant larv^ are fed with a great variety of substances. 

 The quality of the food itself cannot, therefore, be supposed to 

 have a morphogenic value. And even if we admit what seems to 

 be very probable, namely, that a salivary secretion — possibly 

 containing an enzyme — may be administered by some ants at 

 least to their younger larvae, the case against the morphogenic 

 effects of qualitative feeding is not materially altered, as we see 

 from the following considerations : 



3. In incipient ant-colonies the queen mother takes no food 

 often for as long a period as eight or nine months, and during all 

 this time is compelled to feed her first brood of larvae exclusively 

 on the secretions of her salivary glands. This diet, which is purely 

 qualitative, though very limited in quantity, produces only work- 

 ers and these of an extremely small size (micrergates) . 



4. In the honey-bees, on the other hand, qualitative feeding, 

 namely with a secretion, the so-called "royal jelly, " which accord- 

 ing to some authors (Schiemenz) is derived from the salivary 

 glands, according to others (Planta) from the chylific stomach of 



