180 Schrader. 
2. Mated females give rise to broods in which the numbers of 
males and females are approximately equal. 
3. In the maturation of the egg, two polar divisions oceur; and 
the diploid number of chromosomes, which is ten, is reduced to five. 
4. Union of the female pronucleus with the sperm nucleus restores 
the diploid number. This characterizes all cells of the embryo with 
the exception of the giant cells associated with the symbionts. 
5. The first polar body with ten chromosomes, and the second 
polar body with five, fuse; and the resulting polar nucleus contains 
fifteen chromosomes. 
6. This polar nucleus undergoes mitotic divisions, in the course 
of which the number of chromosomes is increased to thirty or more. 
7. The derivatives of the polar nucleus are characterized by the 
number of chromosomes during division, by the number of nucleoli 
during the resting stages, and, more generally, by their large size 
(giant cells). 
8. The giant cells leave the periphery where they are first aggre- 
gated, and migrate to the symbionts, with which they become associated. 
9. The giant cells are definitely distinct from the germ cells. 
References. 
BucHNER, P. 1912. Studien an intrazellularen Symbionten. I. Die intrazellularen 
Symbionten der Hemipteren. Arch. f. Protistenkunde. Bd. 26. 
— 1918. Studien an intrazellularen Symbionten. II. Die Symbionten von Aleurodes, 
ihre Übertragung in das Ei, und ihr Verhalten bei der Embryologie. Arch. f. 
Protistenkunde. Bd 39. 
— 1921. Tier und Pflanze in intrazellularer Symbiose. Gebrüder Borntraeger, Berlin. 
ENMEIS, W. 1915. Über Eientwicklung bei den Cocciden. Zool. Jahrb., Abt. Anat. Bd. 39. 
FRANCOTTE, P. 1898. Recherches sur la maturation, la fecondation et la segmentation 
chez les Polyclads. Arch. Zool. T. 6. 
MACGILLIVRAY, A. 1921. The Coccidae. Scarab Pub. Co., Urbana. 
Martin, F. 1914. Zur Entwicklungsgeschichte des polyembryonalen Chalcidiers Age- 
niaspis (Encyrtus) fuscicollis. Z. wiss. Zool. Bd. 110. 
NACHTSHEIM, H. 1913. Cytologische Studien über die Geschlechtsbestimmung bei der 
Honigbiene. Arch. f. Zellforsch. Bd 11. 
PATTERSON, J. T. 1921. The development of Paracopidosomopsis. Journ. Morph. Vol. 36. 
PETRUNKEWITSCH, A. 1903. Das Schicksal der Richtungskérper im Drohnenei. Zool. 
Jahrb., Abt. Anat. Bd. 17. 
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