XI] 



THE REPRODUCTIVE SYSTEM 



221 



Posteriorly, the egg-strings open into the oviduct (ovd), a thin- 

 walled cylindrical tube, down which the eggs pass one by one. 

 Fertilization is supposed to take place here. The two oviducts 

 open posteriorly in the eighth segment into a large pouch, the 

 spermatheca or bursa (b). The walls of this pouch are very thick 

 and muscular, and are further strengthened by an internally 

 projecting ring or collar of hard chitin. Its cavity is often found 

 to be distended with masses of spermatozoa. Opening dorsally 

 into the bursa, by the union of their two short ducts, is a pair of 

 elongated ovoid sacs, the accessory sacs (as). In mature females 

 these sacs are tightly swollen and smooth, their rounded ends 

 directed forwards and lying at the level of the eighth ganglion (ng 6 ). 

 At other times they are wrinkled and collapsed. In some forms 

 they appear as coiled tubes or caeca. The genital pore opens 

 between the eighth and ninth segments, mid-ventrally. 



2. External Organs (figs. 99-104). 



The external genitalia of the female Dragonfly consist typically 

 of three pairs of ventral processes or 

 gonapophyses, outgrowths of the integu- 

 ment in the region of the genital pore. 

 They begin to develop early in larval 

 life, but have nothing to do with the 

 primitive paired segmental appendages 

 of the abdomen, which, as already stated 

 above, are lost during embryonic life. The 

 three pairs together form the ovipositor, 

 or organ for use in the process of egg- 

 laying. Van der Weele [192] has made 

 an excellent study of the development 

 and structure of this organ. As it is 

 greatly reduced in a large number of 

 Odonata (Gomphinae, Libellulidae], it is 

 necessary to select a form having a 

 well-developed ovipositor, if we would 

 understand its structure correctly. For 

 this purpose we have chosen Synlestes weyersi (fig. 99). 



Fig. 99. Ovipositor of Syn- 

 lestes weyersi Selys, ? 

 ( x 10). ap anterior pro- 

 cesses; mp median pro- 

 cesses; st styles; v valve. 

 Original, chitin prepara- 

 tion. 



