Germ Cells of Leptinotarsa Signaticollis. 167 



To my knowledge, the literature is without data bearing on 

 these later transformations in the nurse cells. Korschelt ('86) 

 described conditions in the young eggs of Dytiscus which resemble 

 these changes to a certain extent, but his descriptions are too 

 meager to admit of much comparison. I am inclined to think that 

 most workers have regarded such appearances as the result of 

 degeneration, and have, therefore, passed over them as of no 

 particular interest. 



II. The Development of the Testis 



The testes of the adult consist of a pair of bean-shaped lobes 

 on either side of the body (Fig, Y). Two ducts, one from each 

 lobe, unite to form a common duct (sp. d.) on one side, which 

 in turn joins with its fellow from the other side to form the 

 median ejaculatory duct. Internally each lobe is made up of 

 radiating follicles, containing cysts of germ cells in various stages 

 of maturation, while in the center is a lumen filled with mature 

 spermatozoa during the breeding season. No suspensory liga- 

 ment comparable to the end thread of the ovariole is present, 

 the organ being supported by the fat bodies, tracheae etc., which 

 are packed about it. 



In the early stages of development the organ bears but slight 

 resemblance to the adult, each lobe being somewhat spindle-shaped 

 and looking very much like a single ovariole at a corresponding 

 stage (Fig. Z, A).' Histologically, as in the ovary, two kinds of 

 cellular elements can be distinguished — germ cells and epithelial 

 cells (Fig. 17, 18). Here too, there is the same tendency for several 

 of the latter to be grouped around a single germ cell (Fig. 36) . Fig. 

 17 shows the first stage in cyst formation in which, as in the ovary, 

 the epithelial cells exhibit the same relationship to the completed 

 cysts as they do to the single germ cells of earlier stages. The 

 contents of each cyst are the descendants of a single mother-cell. 



1 Each lobe terminates in a cap of epithelial cells resembling the expanded 

 base of the terminal thread of the ovariole of the adult female. A considera- 

 tion of the significance of these cells together with a more complete description 

 will be given in a future publication. 



JOURNAL OF MORPHOLOGY. — VOL. 21, NO. 2. 



