loo PHILIP P. CALVERT. 



Hagen has recorded instances of the copulation of different species, hut no- 

 thing is known of their progeny (Ent. Weekly Intel. 1857, pp. 62, 63. Stet. Ent. 

 Zeit. xix, p. 44, 414-15, 1858). 



OVIPOSITION. 



Owing to the separatiou of the intromittent organ from tlie ex- 

 ternal opening of the vas deferens in the male, an essential prelude 

 to the act of copulation is the filling of the vesicle of the penis with 

 sperm. This is accomplished by the curving of the abdomen, ven- 

 trally upon itself so that the ventral surfaces of the ninth and second 

 segments come in contact. While no precise details have been re- 

 corded, it seems probable that in the Zygoptera the sperm passes di- 

 rectly from the vas deferens through a fissure on the free end of the 

 vesicle to its interior, and the penis is filled by applying it to the 

 vesicle. In the Anisoptera the sperm passes through the penis into 

 the vesicle. This preliminary stage ended,* the male flies after a 

 female, seizes her by his feet, and then clasps her prothorax with his 

 abdominal appendages. She then curves the apex of her abdomen 

 ventrally forwards and upwards, so that the vulva shall come in con- 

 tact with his accessory genital organs, and the sperm is introduced 

 into the vulva by the penis. During copulation, therefore, the male 

 is above and in front of the female ; the heads of both are turned in 

 the same direction. While in most of the groups the act of copula- 

 tion lasts but for a very short time and takes place while flying, it 

 would appear that among the Agrioninje a considerable period 

 elapses between the clasjiing of the female's prothorax and the curv- 

 ing of her abdomen to meet that of the male, and that the impreg- 

 nation is effected when at rest. The spermatozoa upon being received 

 into the vagina pass into the receptacula seminis and the bursa 

 copulatrix, and tlie eggs are fertilized as they pass the openings of 

 these ])()uches on their way down the vagina. 



Oviposition, as a general rule, immediately follows copulation. In 

 the AgrionidiTe,f the Aeschninse, and probably in the Petal uroid 

 Gomphinje and the Cordulegasterinse, the eggs are laid within the 

 tissues of phiuts below the water's surface in conformity with the 



* Todd records the male of Lestes as charging the seminal vesicle after the 

 female had been seized (Amer. Nat. xix, pp. 306-7). 



t Apparently the only observation which conflicts with this statement is that 

 of Walsh (Proc. Ent. Soc. Phila. ii, p. 322), who "observed that Hetierina 9 flirts 

 her eggs into the open rivei-, without attaching them to aqnatic plants." This 

 assertion should he tested by further observations. 



