Testis of Leptinotarsa Signaticollis. 



487 



condition, seen in the inner layer, that the present paper has to 

 deal. 



In order to facilitate a complete understanding of the facts I 

 shall outline briefly the main features of the development of the 

 testis as a whole. In the earliest stage of larva studied each tes- 

 tis consists of a pair of spindle-shaped lobes (fig. 2, A) showing no 



Fig. 3 Longitudinal section of the distal end A, and the proximal end fi of a 

 lobe of a larval testis, e.c, terminal cap of epithelial cells; s.d., sperm duct; c, 

 cysts of germ cells; m, mitotic division in a cell of the sperm duct; t, thread-like 

 rudiment comparable to the terminalt hread of the ovariole. X 265. 



Fig. 4 Longitudinal section of a larval testis about two or three days older than 

 that shown in the preceding figure. A, distal end; B, region slightly proximal 

 to A, showing the accumulation of epithelial cells that marks the first step in the 

 degeneration process. X 265. 



trace of follicular arrangement, and terminating distally in a 

 cap (a) of lightly staining epithelial cells. The first step in the 

 further development of the organ consists in an enlargement in a 

 transverse direction without a corresponding increase in length 

 (fig. 2, B). In the next stage (fig. 2, C) the follicles appear as 

 radial outpocketings from the sides of the lobes. Fig. 2, D, shows 



