246 
SIDNEY I. KORNHAUSER 
6. All chromosomes divide equationally in the second sper- 
matocyte division, giving rise to female determining spermatozoa 
with 11 autosomes and two x-chromosomes, and male determin- 
ing spermatozoa with 11 autosomes and a y-chromosome. 
7. The y-chromosome of the spermatocyte is chemically and 
morphologically rather unlike the x-chromosomes during the 
growth period up until the late strepsinema, when it gives off a 
nucleolar spherule which takes mitochondrial stains. 
Granville, Ohio, June 28, 1921, 
9. BIBLIOGRAPHY 
Brauns, Fr. 1912. Die Entstehung der Nahrzelle und die Bedeutung derselben 
flir das wachsende ei bei Forficula auricularia L. ; Sitzungsb. u Abhandl. 
d. naturf. Gesellsch., Rostock, N. F., Bd. 4 (245). 
Castle, W. E. 1921. A New Type of Inheritance. Science, N. S., Vol. 53, 
No. 1371, pp. 339-342. 
Pantel, J. 1912. Recherches sur les Dipteres a Larves Entomobies. II. Les 
enveloppes de Poeiif avec leurs dependances, des dcgats indirectes du 
parasitisme. La Cellule, T. 29, Fasc. 1, pp. 7-289. PI. I-VII, 25 text 
figs. 
Payne, F. 1914. Chromosomal Variations and the Formation of the First 
Spermatocyte Chromosomes in the European Earwig, Forficula sp. 
Journ. Morph., Vol. 25 No. 4, pp. 559-581, PI. 2, text figs. 7. 
Randolph, Harriet. 1908. On the Spermatogenesis of the Earwig Anisolabis 
maritima. Biol. Bull., Vol. 15, No. 2, pp. 111-114. 
Stevens, Nettie M. 1910. An Unequal Pair of Heterochromosomes in For- 
ficula. Jour. Exp. ZooL, Vol. 8, No. 2, pp. 227-234, 3 pi. 
ZwEiGER, H. 1906. Die Spermatogenese von Forficula auricularia L. Jena 
Zeitschrift f. Natur. wiss., Bd. 42, pp. 143-169. 
10. EXPLANATION OF PLATES 
All drawings were made with the aid of a camera lucida. A 1.5 mm. Zeiss 
apochromatic objective and a 20X compensating ocular was the optical combi- 
nation used. All figures were drawn at 3300 diameters magnification and subse- 
quently reduced, in Plate XXIV the reduction being about one-third and in 
Plates XXV and XXVI the reduction being about two-fifths. 
Plate XXIV 
Figs. 1-4. Oogonia, metaphase plates, polar view, 26 chromosomes. 
Figs. 5-8. Somatic mataphase plates, polar view from female embryo, 26 
chromosomes. 
Figs. 9-12. Spermatogonia, metaphase plates, polar view, 25 chromosomes. 
Figs. 13-16. Somatic metaphase plates, polar view from male embryo, showing 
25 chromosomes. 
