46 



plicated is found in most forms. The posterior hair has f. insl. in Ch. graniilatns 

 C. K. a small ventral tooth in all the tarsi, while Ch. lampropsalis sp. af. only shows 

 this structure in the posterior hair of the first pair of legs in the male (PI. Ill, 

 figs. 4 a, /ie; 6 d), in contrast to Ch. siiperhiis n. sp., in which it is found in the 

 fourth tarsus of the male; in the two last mentioned species we have accordingly 

 a sexual character in the structure of this hair. 



6. Coxal Sac of "Lophochernes Sim." 



Introductory remarks. Under my examination of the male of Chelifer 

 Mortensenii n. sp. I noticed near the base of the fourth pair of coxae a dark spot; 

 on further examination I found to my astonishment a very remarkable organ, of 

 which no description was found in literature. These two spots with a dark dot 

 in the middle have been figured by Croneberg (1889. 45. taf. X, fig. 4) in Ch. can- 

 croides L., but he has scarcely realised their nature, as he does not mention them 

 in the text of his paper. According to private communication, Professor Sidney J. 

 Hickson "saw the Coxal sac years ago, but has not published the observation"; the 

 same gentleman has kindly sent me specimens of a new species, Ch. siiperbus n. sp. 

 for examination, on account of which I ask him to receive my best thanks. During 

 a visit to London I examined in the British Museum a male of Ch. Socotrensis With 

 and gave there a description of the coxal sac of this species as a kind of preliminary 

 note (1905. 21. pp. 135 — 1;^6); the surfaces, designated dorsal and ventral in this 

 paper, seem really to be the anterior and posterior ones, a question which I was 

 not able to settle with a single coxa at my disposal without material for com- 

 parison. 



The coxal sac, the structures and remarkable variations of which in several 

 forms will be described below, seems always to be present in the males of those 

 species of Chelifer Geof., which are naturally referred to the subgenus ''Lopho- 

 chernes Sim." (cf. below); this organ, the presence of which is one of the principal 

 characters of this group of Chelifer Geof., provides alwaj's a sexual character of 

 value and very often specific ones of great importance, even if rather difficult to 

 investigate. A detailed description of its form in Ch. Mortensenii n. sp. will first be 

 given, and thereafter the variations of a good many other species. 



1. Ch. Mortensenii n. sp. (PI. II, figs. 9 a-c). — If the coxae of the male be 

 examined in their natural position, an almost circular opening is seen, situated 

 near the interio-poslerior corner; a tuft of hairs is directed inwards and back- 

 wards through this opening, and the surrounding skin is rather thin and trans- 

 parent (PI. Ill, fig. 1 f). If the coxa itself be dissected out and examined from 

 above, we will find, that the hollow of it is partly occupied by an elongated 

 chitinous sac, as long as two thirds of the coxa and half as broad. This sac, 

 which is somewhat flattened and widened out towards its summit, but especially 



