222 



Heredity and Environment 



FIG. 83. YOUNG FISH. On the right a normal individual with two eyes ; 

 on the left cyclopean monsters with one eye; produced by treatment with 

 magnesium solutions. (From Stockard.) 



but did not change into frogs; if fed on the adrenal gland they 

 produced extremely light-colored forms. If canary birds are 

 fed on sweet red pepper they become red in color. If the larvae 

 of bees are fed on "royal jelly," which is a bee food rich in fats, 



FIG. 84. THE THREE CASTES OF THE HONEY BEE. A, worker or imper- 

 fect female; B, queen or perfect female; C, drone or male. The differ- 

 ences betwen workers and queens are produced by the type of food sup- 

 plied to the larvae. 



