On a new Trichocera /i-om Siberia. 431 



tliat liave been described — Pahidina (3), Dithinia (9), Tan- 

 ganyikia and Melania (8) — tlie brood-pouch opens diiectly to 

 the exterior by a terminal (vaginal) pore. On the otlier 

 hand, in Cyclostoma elegans (4) the vaginal aperture is 

 aj)parently not at the extremity of the brood-pouch, as the 

 latter " est un organe tubulaire termine inft^rieurenient en 

 cul-de-sac et presentant lat^ralement une large fente, la vulve." 



Works referred to. 



(i) Bernard, F. Bull. Sci. France et Belgique, xxii. (1890). 



(2) Boycott, A. E. Journal of Couchology, xvi. no. 2 (1919). 



(3) Bronn, H. Kia^sen und Ordnuugen des Thierreichs. 



(4) Garxault, p. Actea Soc. Linn, Bordeaux, xli. (1887), 



(5) Henking, H. Bei-ichte Naturf. Ges. Freiburg-, vii. (1894), 



(6J Lkhmann, R, Schnecken und Muscheln .... Stettins, (Cassel, 

 1873), 



(7) Meyer, H., nnd Mobius, K. Fauna der Kieler Bucht, ii. (1872). 



(8) Moore, J. E. S. Quart. Journ. Micr, Sci. xli. (1898). 



(9) MoQuiN Tandon, a. Moll, de France (Paris, 1855). 



(10) Quick, H. E. Journal of Conchology, xvi. no. 3 (1920), 



(11) Handles, W. B, Quart. Journ, Micr, Sci. xlviii. (1905). 



(12) SiMROTH, EI. Zool. Anz. Jahrg. iv. no. 94. 



(13) Smith, E. A. Journal of Conchology, tI, (1889). 



(14.) Woodward, B. B. Ann, & Mag. Nat. Hist. ix. (1892). 



EXPLANATION OF PLATE XV. 

 Fig. 1, Pahidestrina jenhinsi. Transverse section of mouth, showing 



cuticle (c) and mandibles (?«.), [Cam. 4 oc. x6 obj. Reich.] 

 Fig. 2. Ditto. Diagiauimatic transverse section through ajsophagus. 



[4 OCX 6 obj. Reich.] 

 Fig. 3. Ditto. Crystalliue style. [Cam. 4 oc. x3 obj. Reich.] 

 Fig. i. Ditto. Section through stomach-wall, c, = cuticle, [Cam, 4oc. 



X6 obj. Reich.] 

 Fig. 5. Ditto, Section through gill-filaments and supporting lamellte, 



[Cam. comp. oc. X6 obj. Reich.] 

 Fig. 6. Ditto. Heart: section through auricle (a.) and ventricle (v.). 



[Cam. 4 OCX 6 obj. Reich.] 

 Fig. 7. Ditto. Sections through (A) junction of oviduct with yolk-bearing 



ovarian tubule ; (B) ovarian tubule, showing oocytes and yolk 



in epithelium, 2/, = yolk; orf, = oviduct. 

 Fig. 8. Ditto. Section through junction (ay.) between spermatheca and 



vagina, nnd connection of albumen-gluud {eg.) and vagina (v.) 



with brood-pouch {bp.). oJ, = oviduct. [Cam. 4 oc.x6 obj.J 



LVIII. — -4 neio Trichocera//-o?» Siberia (Diptera Pohjneura). 



By F. W. Edwards. 



(Published by permission of the Trustees of the British Museum.) 



Among a collection of mosquitoes recently sent me for deter- 

 mination by Prof. Yngve Sjostedt, of Stockholm, was a single 

 male specimen of a Trichuccra which, though dillcring little 



