[44] Copulation in Ticks 323 



We have dwelt thus at length upon the process of copulation in 

 0. moubata, because until now it has never been understood how the 

 male impregnates the female. 



As bearing on the process of copulation in Ixodidae we would add 

 the following remarks : 



We have stated elsewhere that the genus Ixodes (group Prostriata) 

 is widely separated from the other genera of Ixodidae (group Meta- 

 striata) in important points of anatomical structure. In Ixodes the anal 

 grooves surround the anus in front, the sexes show marked dimorphism 

 in respect to the structure of the hypostome, and in certain species the 

 sexes are frequently found coupling upon the host. In Ixodes the male 

 inserts his mouthparts into the female sexual orifice as a part of the 

 sexual act. In none of the Metastriata has a similar method of coupling 

 been observed ; here the males remain attached for longer periods to 

 the host and they do not appear to wander about upon it as do some 

 species of Ixodes whose males infest the host together with the females. 

 In Metastriata the females and males are found attached to the host so 

 that in many cases the venters of the sexes are apposed. 



We have discovered that in the Metastriata (including the genera 

 Haemaphy salis, Dermacentor, Rhipicentor, Rhipicephalus, Boophilus, 

 Margaropus, Hyalomma, Amblyomma and Aponomma) all the males 

 possess a chitinous apron or flap covering the sexual aperture. The 

 apron arises from the integument anteriorly to the sexual aperture and 

 is directed backward over the aperture ; it is frequently serrated along 

 its rounded posterior border which is free. The apron can be readily 

 lifted by inserting a fine needle between it and the body surface ; it is 

 very thin at the free margin, whereas it grows gradually thicker toward 

 its origin. The apron is absent or rudimentary in the females. 



Now we find that in Ixodes the males do not show an apron, or it is 

 very rudimentary in character. On the other hand the apron, though 

 very thin, may be very well developed in the females ; it is best seen in 

 young specimens. 



The presence of the apron in the males of Metastriata and its absence 

 in Ixodes is very suggestive, and, taken together with the other dif- 

 ferences, indicates that copulation may possibly take place in another 

 manner in the Metastriata to what it does in Ixodes. The mechanism 

 of copulation in Metastriata still remains to be determined and the 

 significance of the apron requires to be explained. 



