ANT. S. 



of it that is assimilated by the living tissues of the larva. In other 

 words, the larva i- not altogether a passive organism, compelled to 

 utilize all the food that is forced upon it, but an active agent, at least 

 to a considerable extent, in determining its own development. And the 

 physiologist might have difficulty in meeting the assertion that the 

 larva utilizes only those portions of the proffered food that are most 



conducive to the specific, prede- 

 termined trend of its development. 

 In the second place, while experi- 

 ments on many organisms have 

 shown that the quantity of as- 

 similated food may produce great 

 changes in size and stature, there 

 is practically nothing to show 

 that even very great differences 

 in the qualitv of the food can 

 bring about morphological differ- 

 ences of such magnitude as those 

 which separate the queens and 

 workers of manv ants. 



FIG. 65. Gynandromorph of Formica 

 microgyna ; head almost purely female, 

 gaster male, thorax, petiole and legs male 

 on left, female on right side. (Original.) 



These more general consider- 



ations are reinforced bv the fol- 

 lowing inferences from the 

 known facts of larval feeding: 

 i. There seems to be no valid reason for supposing that the mor- 

 phogeny of the queens among the social Hymenoptera depends on a 

 particular diet, since with the possible exception of the honey- and sting- 

 less 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 of the 

 hone}-- and stingless bees, the question of the morphogenic value of the 

 larval fond may be restricted to the worker forms. 



2. Observations show that although the nature of the food admin- 

 istered to the larvse of the various social insects is often very different, 

 even in closely related species, the structure of the workers may be 

 extremely uniform and exhibit only slight specific differences. Among 

 ants, as we have seen (p. 74), the larvae 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 



