462 LECTURE XIX. 



Their ducts are sometimes long and intertwined ; e. g. Salticiis, 

 Thomisus* 



The most careful observations, repeated by the most attentive and 

 experienced entomologists, have led to the conviction that the ova 

 are fertilised by the alternate introduction into the vulva of the 

 appendages of the two palpi of the male. Treviranus's supposition 

 that these acts are merely preliminary stimuli, has received no con- 

 firmation, and is rejected by Duges, Westwood, and Blackball ; and 

 with good reason, as the detection of the spermatozoa in the palpal 

 vesicles has shown. At the same time, the most minute and careful 

 research has failed to detect any continuation of the vas deferens 

 into the terminal erectile sac of the palp, or any other termination 

 than the abdominal opening above described. Duges offers the very 

 probable suggestion that the male himself may apply the dilated 

 cavities of the palpi to the abdominal aperture, and receive from the 

 vasa deferentia the fertilising fluid, preparatory to the union ; and 

 the discovery of the spermatozoa at an earlier stage of development 

 in the abdominal testes, which development is completed after the 

 transference of the semen to the vesiculre, equally demonstrates the 

 respective shares which the two widely separated parts of the male 

 apparatus perform in these remarkable Articulate animals. The 

 analogy of the separate location of the testes and vesicular seminales 

 in the dragon-fly will no doubt present itself to the mind. Certain 

 it is that an explanation of this singular condition of the male ap- 

 paratus, in which the intromittent organ is transferred to the remote 

 and outstretched palp, is afforded by the insatiable proneness to slay 

 and devour in the females of these most predacious of articulated 

 animals. 



The young and inexperienced male, always the smallest and 

 vv^eakest of the sexes, has been known to fall a victim, and pay the 

 forfeit of his life for his too rash proposals. The more practised 

 suitor advances with many precautions, carefully feels about with his 

 long legs, his outstretched palpi being much agitated ; he announces 

 his approach by vibrating the outer border of the web of the female, 

 who answers the signal, and indicates acquiescence by raising her 

 fore-feet from the web, when the male rapidly approaches ; his palpi 

 are extended to their utmost, and a drop of clear liquid exudes from 

 the tip of each clavate end, where it remains attached, the tips them- 

 selves immediately coming in contact with a transverse fleshy kind of 

 teat or tubercle protruded by the female from the base of the under 

 side of the abdomen. After consummation, the male is sometimes 



* XXIV. p. 547. 



