Testis of Leptinotarsa Signaticollis. 491 



Fig. 5, A, B, is from a larva approximately two days older than 

 the preceding. The separate follicles have begun to form and the 

 terminal epithelial cap is in the shape of a papillary projection 

 from the flattened distal surface of the lobe. The accumulation 

 of epithelial cells has grown in amount. (With the exception of 

 figs. 1, 2 and 7, all figures are drawn at the same magnification). 

 In the distal (upper) part of this region, deeply staining granules 

 within and without the epithelial cells mark the beginning of the 

 second stage in the degeneration process. 



In the case of the ovariole the conclusion^vas reached that the 

 epithelial cells of the terminal chamber are derived from the 

 pale-staining cells of the terminal thread. Somewhat similarly, 

 in the testis, the cells of the degenerated area have their origin 

 in the terminal cap, which structure is apparently homologous 

 with the enlarged base of the terminal thread of the ovariole. 

 Fig. 2 shows direct continuity between the cells of the degen- 

 erated area and those of the terminal cap. Such a condition per- 

 sists throughout the greater part of the pupal period; that is, 

 until the central accumulation of epithelial cells reaches its max- 

 imum size. Toward the end of this period of development the 

 two regions become separated by a layer of spermatogonia, as 

 shown in fig. 7 which represents a section of an entire pupal 

 testis. 



Examination of the central cells (d) of this figure under higher 

 magnification shows that disintegration has progressed in the 

 distal part, although the cell outlines still persist. The prin- 

 cipal change is the large increase in number of cells composing the 

 mass, which is spheroidal in form and approximately fills the cen- 

 tral cavity of the testis. 



With the disappearance of the connection between the cells 

 of the terminal cap and those of the central region, degeneration 

 and cytolysis among the latter proceeds very rapidly. As the 

 process goes on the mass of cells as a whole shrinks toward the 

 distal end of the central cavity, until in the fully developed testis 

 of the imago it has the appearance represented in fig. 8. Fig. 

 9 is a section taken at right angles to the axis of the testis and 



