420 ROBERT W. HEGNER 



is only possible to suggest that they may be derived from (1) 

 the cytoplasm of the egg, (2) the cytoplasm of the nurse cells, 

 (3) chromatin from the germinal vesjcle, (4) chromatin from the 

 nurse cells, (5) nucleolar substance from either germinal vesicle 

 or nurse cells or both, and (6) bodies of mitochondrial nature. 



(3) The spermatogonial divisions and formation of cysts in the 

 testes of Leptinotarsa decemlineata. The material on which this 

 section is based consists of a complete series of stages from the 

 time the male germ gland can be recognized in the half grown 

 embryo to the adult condition. Embryos and young larvae 

 were fixed in toto in hot Tower's fluid and sectioned entire. The 

 germ glands of older larvae, pupae, and adults were dissected in 

 Ringer's solution and transferred at once to the desired fixing 

 fluid. Meves', Gifeon's, and Carnoy's solutions were chiefly 

 used for this purpose. Sections were stained with iron hema- 

 toxylin, Mayer's acid hemalum, and safranin and light green. 

 All of the figures were drawn from preparations made from 

 material fixed in Carnoy and stained with iron hematoxylin. 



The form and position in the abdomen of the adult male 

 reproductive organs are shown in figure 10. There are two 

 pairs of testes, one pair on either side of the body. Each testis 

 consists of a large number of follicles radiating out from near 

 the center. Figure 11 is a diagram of a longitudinal section 

 made from the testis of an old larva. At the lower end is attached 

 the sperm duct (s.d) which is connected with a cavity (c) within 

 the testis. Just above this cavity is a region containing sper- 

 matozoa; above this region is a mass of spermatogonia (sg) not 

 yet within cysts; and this mass is capped by a small group of 

 epithelial cells (^.c). The major part of the testis is composed 



Fig. 9 Leptinotarsa decemlineata; diagram of an ovarian tubule showing 

 various stages in the development of the oocyte. The figures refer to the posi- 

 tions of cells shown in the figures in plate 9. 



Figs. 10 to 12 Leptinotarsa decemlineata. 10, Reproductive organs of male. 

 11, Longitudinal section through testis of full grown larva. 12, Transverse section 

 through testis of full grown larva in region indicated by line labelled 12 in fig. 11. 

 c, cavity of testis; cy, region of cysts; s.d, sperm duct; sg, spermatogonia; sp, 

 spermatozoa; t.c, terminal cap. 



