GERM CELLS IN THE ARTHROPODA 143 
grate, so they probably take part in development 
after becoming associated with some other part of 
the egg. If these nuclei were qualitatively different 
they should produce germ cells and other varieties of 
cells in whatever region they chance to reach. It 
is evident that they are not potentially different 
and that their ‘“ prospective potency” and ‘“ pro- 
spective significance” do not coincide. The cyto- 
plasm is, therefore, the controlling factor at this 
stage in the germ-cell cycle, although cytoplasmic 
differentiations are for the most part invisible and 
probably the result of nuclear activity during earlier 
stages. 
Hymenoptera. A number of papers have ap- 
peared which contain references to the germ glands 
of Hymenoptera (Hegner, 1909, pp. 245-248). 
The most important of these from the standpoint of 
the present discussion are: (1) Silvestri (1906, 1908) 
and Hegner (1914b) on some parasitic species, and 
(2) Petrunkewitsch (1901, 1903), Nachtshemm (1913), 
and others on the honey-bee. 
In an endeavor to test the “ Dzierzon theory,” 
that the eggs which produce drone bees are normally 
unfertilized, Petrunkewitsch (1901-1903) discovered 
some usual maturation divisions. In “‘ drone eggs” 
the first polar body passes through an equatorial 
division, each of its daughter nuclei containing one- 
half of the somatic number of chromosomes. The 
inner one of these daughter nuclei fuses with the 
second polar body, which also contains one-half of 
the somatic number of chromosomes; the resultant 
