1917-18.] Germ-Banc! in the Egg of the Holly Tortrix Moth 157 
globules staining very darkly with Heidenhain’s hsematoxylin ; (2) yolk 
bodies, rendered polygonal through mutual pressure, and taking the usual 
cytoplasmic stains, especially eosin ; and (3) a sprinkling of much more 
minute granules, resembling those of the inner layer of the periplasm 
in their intense affinity for basic stains. 
Maturation of the ovum takes place, as in the bee (see Nachtsheim), 
about the time of oviposition. In the section shown in PI. I, fig. 1, which 
is from an egg fixed about an hour after oviposition, the female pronucleus 
is seen near the centre, while the three polar nuclei lie in a thickening 
of the periplasm situated on the convex side of the egg. The cytoplasm 
immediately surrounding the polar nuclei, i.e. in the central part of the 
thickening, is more finely granular and forms the “ Richtungsplasma.” 
Two of the polar nuclei are distinctly smaller than the third ; these are the 
daughter products of the first polar body, while the larger nucleus is the 
second polar nucleus. All are true nuclei, and not merely chromatin masses * 
(“ Chromatingruppen ”) such as are figured and described by Nachtsheim 
in his work on the egg of the bee. The female pronucleus has apparently 
no special cytoplasmic envelope, but at one point on its periphery is a 
small accumulation of yolk-plasm. The male pronucleus is seen nearer 
the anterior end of the egg, surrounded by an attraction sphere of 
cytoplasmic radiations in which it is somewhat eccentrically placed. 
When the temperature is high, 68 -70° F., the first division of the zygote 
nucleus takes place, near the centre of the anterior half of the egg, two or 
three hours after oviposition. The second division follows rapidly, and 
without much shifting of position ; so that, about midnight, four nuclei 
may be found, each already surrounded by its little “ island ” of cytoplasm, 
with radiating processes, finely granular and mainly basophil, like the 
cytoplasm of the inner stratum of periplasm. At the time when the egg 
contains eight dividing nuclei these are still in close proximity, and the 
prolongations of their cytoplasm appear to be in contact ; but by the time 
that sixteen nuclei are in the dividing state, they are spreading throughout 
the yolk, so as to become distributed fairly equally. 
After a few more nuclear divisions the resulting amoeboid cells are seen 
to be tending towards the periplasm, both nuclei and cytoplasm elongating 
in the direction of movement. The cells usually enter the periplasm 
diagonally, as is well seen when mitosis occurs at this juncture, and in 
these cases it appears that one daughter cell passes into the periplasm, 
while the other remains in the yolk. 
* Henking describes and figures the polar bodies of Pieris brassiest as true nuclei, 
though in his studies of the eggs of otter insects he finds merely chromatin masses. 
