220 SUMMARY OF CURRENT RESEARCHES RELATING TO 



5. Arachnida. 



Mating in Cribellate Spiders.* — Jeanne Beiiand has studied the 

 mode of copulation in cribellate spiders, especially in Dictyna vividissima^ 

 a small form in which the female is of a delicate green colour, while 

 the smaller male has the cephalothorax and appendages rust-coloured 

 and the abdomen green. The two sexes are usually found in their 

 different retreats on the surface of a large green leaf, such as that of 

 Aralia, or, more often, one on the upper and one on the under side. The 

 whole process of wooing and mating is described and illustrated. A 

 distinctive feature is that the cheliceraB of the female grasp those of the 

 male, and this position is maintained throughout. The web of this 

 species and of Filistata testacea is also described and figured, and a pre- 

 liminary note made as to the function of the cribellum and calamistrum. 



New Mites from Lizards.t — Stanley Hirst describes some new 

 mites from lizards — two new species of Pterygosoma ; a new genus, 

 Geckohiella, nearer to Pterygosoma than to Geckobia ; seven new species 

 of Geckobia ; and P imeliaphilus tenuipes sp. n. With the probable 

 exception of the last, all are true blood-sucking parasites. 



Evolution of Indo-Australian Thelyphonidse.l — F. H. Gravely 

 takes a survey of the known forms, and finds that evolution has chiefly 

 affected three structures : (1) the tibial apophyses of the male (probably 

 in connexion with sexual processes) ; (2) the tarsi of the antennif orm legs 

 of the female (at about the place where the male holds them between his 

 chelicerag during courtship) ; (3) the genital sterna of both sexes. The 

 geographical distribution of the genera is discussed in relation to these 

 characteristics. 



Cavernicolous Acarina.§ — L. G. Neumann reports on forty-three 

 collections of Ixodidge from different grottos. Most of them consist 

 solely of Ixodes (Eschatocephahis) vespertilionis C. L. Koch, which is truly 

 cavernicolous. The only other species is ,/. hexagonus, introduced into 

 grottos by small mammals. In the first-named species the adult males 

 were never found except on the walls of the grotto ; the parasitism on 

 bats seems to be restricted to larvte, nymphs, and females. 



e. Crustacea. 



Revision of British Idoteidae. — Walter E. Collinge has revised the 

 British representatives of this family of marine Isopods. A useful 



* Arch. Zool. Exp6r., Iv. (1916) pp. 53-66 (8 figs.). 

 t Ann. and Mag. Nat. Hist., xix. (1917) pp. 136-43. 

 X Records Indian Museum, xii. (1916) pp. 59-85 (4 pis.). 

 § Arch. Zool. Exp^r., Iv. (1916) pp. 515-27 (1 pi.). 

 ' li Trans. R. Soc. Edinburgh, li. (1917) pp. 721-60 (11 pis.). 



