2 Annals of tJie South African Museum. 



circular area, which it divides into a right and left half, each half 

 being formed of a piece of hardened cuticula (genital sclerite), 

 movably articulated with the adjacent half-sternite by means of a 

 strip of soft skin. This soft skin bears no hairs and is usually sunken 

 in, forming a curved groove. It is characteristic of the adult male 

 that the, oval or circular area is ahoays large, generally about half as 

 long as the sternite itself, but sometimes longer.* 



In immature males a similar pair of genital sclerites occurs, but 

 they are much smaller, being only i-i- of the sternite in length. 



atcf.% 



JUV. <? JIM/. O 



FIG. 1. First abdominal sternite of various specimens of Solpuga venator, Poc. 

 {x 3 times), all from the same locality (Dunbrody). 



Adult female. In the adult female the genital sclerites are absent 

 and the sternite is generally deeply grooved along the median line. 

 The sexual opening is very large and conspicuous, being situated in 

 the soft skin under the posterior region of the sternite, and of course 

 not visible until this is lifted. Moreover, the hind margin of the 

 segment is cleft or emarginated, generally strongly so, in the middle, 

 the hind median angles of the half-sternites not being united by soft 

 skin quite up to the hind end. The depth of this emargination or 

 incision, as well as the shape of the sexual opening, varies consider- 

 ably in the different species, and may be used as a specific or group 

 character. 



The immature female may be recognised from the immature male 

 by the absence of the genital sclerites and from the adult female by 

 the absence of a large and conspicuous sexual opening and generally 

 also by the absence of the posterior median incision. 



* In the species which were more closely examined (8. venator, S. hostilis) the 

 hairs n the genital sclerites are pointed and differ from the majority of the hairs 

 on the rest of the sternite, which are mostly conspicuously forked at the apex. 



