310 * Genus Ixodes 



about 40 seconds for each egg to issue from the female. After the egg 

 issues, the vagina is retracted within the body and Genu's organ is also 

 retracted. Gene" records that he once observed the process of oviposition 

 in the case of a female whose capitulum had been torn off when the 

 tick was removed from a dog. To study the process, he placed the 

 ticks upon their backs and cut off their legs so as to render them 

 immovable. The female, according to Gene", at first depresses the 

 capitulum so that it is applied to the ventral surface of the body. The 

 palps and chelicerae being divaricated, Gene's organ is then alternately 

 protruded and retracted "in a hesitating manner," after which it is 

 rapidly protruded to its full extent, hiding the capitulum whilst it 

 receives the egg from the protruded vagina, or ovipositor. Gene's organ 

 is quite clearly stated to emit a sticky secretion upon the surface of the 

 eggs whilst it overlaps them for a period of four to five minutes. If the 

 organ is pricked with a needle, oviposition ceases for a while, and when 

 continued the eggs are laid directly from the oviduct ; but eggs laid in 

 this manner are not glossy and they soon dry up and become shrivelled. 

 Gene supposed that, in addition to covering the eggs with the sticky 

 secretion, which may serve to harden the chitinous envelope of the egg, 

 that the organ may convey spermatozoa in some way from the female's 

 uterus to the egg as she is laying. He did not, however, pretend to explain 

 how fertilization actually takes place 1 . The ovipositor and Genu's organ 

 having been retracted, the egg is left lying upon the capitulum, which 

 now resumes its normal position and shovels the egg backward on to 

 the scutum. This curious process is then repeated as long as the tick 

 continues to oviposit; the newly-laid eggs push the older ones backward 

 in a heap upon the dorsum of the tick, the anterior part of the tick thus 

 gradually disappearing in the heap of eggs. 



Bertkau (1881, p. 148) repeated the experiment of pricking Gene's 

 organ, and confirmed the observation that eggs laid without being covered 

 by its secretion subsequently shrivel up. This result was also obtained 



1 Railliet (1895, p. 706, Fig. 480) reproduces a figure of an ovipositing ricinus from 

 Gene (1848), and briefly refers to the process and to the everted vagina or oviduct serving as 

 an ovipositor or " oviscapte"; he refers to Geno's organ as the "bourse seminale de Gene," 

 or "vessie bilobee." Wheler (1899) calls it the " dorsal gland." Samson (1909, p. 223) 

 calls it the " Subscutalblase." Dutton and Todd (1905 b, p. 17) describe and figure the same 

 structure in Ornilliodorus moubata as a " pulmonary sac" and Brumpt (1910, p. 523, Fig. 

 363) calls it the " cephalic gland," following Christophers (1906, p. 95), who gave this name 

 to the structure in O. savignyi. None of these names adequately describes Genu's organ. 

 We give pre-eminence to Gene's observations because they have been generally ignored by 

 writers on the subject. 



