FORM, GROWTH, AND CHANGE 27 



period, and discharges them as required for fertilizing the eggs 

 as these are laid. 



The sperm-cells (or spermatozoa) (Fig. 15 sp) are minute cells, 

 capable of active motion because the cell-body is drawn out 

 into a long whip-like process or flagellum. They are developed 

 in the male grasshopper's testes (Fig. 15 T) small rounded 

 paired bodies situated in the dorsal abdominal region. From 



U 



1) 



FIG. 14. FEMALE REPRODUCTIVE ORGANS OF AN INSECT. 



o, ovaries ; od, oviduct ; v, vagina ; s, spermatheca ; sg, sperma- 

 thecal gland ; be, bursa ; eg, colleterial glands. Magnified and 

 diagrammatic. A, single ovarian tube showing primordial germ-cells 

 in the terminal filament (<) and ripe eggs at hinder end. Highly 

 magnified. From Comstock, "Introduction to Entomology ". 



each testis a delicate tube the vas deferens (Fig. 15 v d}- 

 leads backwards and downwards, the two vasa deferentia open- 

 ing into the seminal vesicles (Fig. 15 s v) composed of a mass of 

 small tubules, whence the chitin-lined ejaculatory duct (Fig. 



