ZOOLOGY AND BOTANY/ MICROSCOPY, ETC. 205 



therefore be considered morpliologically as a secondary and more 

 complex system. 5. The male and female excretory dncts of the 

 generative glands are homologous. 6. The cavities of the oviducts, 

 uterus, and vagina in the female, and of the vasa deferentia, accessory 

 organs, and ductus ejaculatorius in the male arise independently of 

 each other and only come into connection in a secondary manner, 

 A full account, with illustrations, of the investigations made by 

 the author in the different orders of insects is to be published 

 hereafter. 



Anatomy and Development of the Ovary in Diptera.* — In 

 insects generally, A. Jaworowski finds that each ovary is developed 

 from a single embryonic cell which in Chironumus lies between the 

 body-wall and the intestine ; in a freshly-hatched larva of this gnat 

 the gland contains two cells, imbedded in the protoplasm of the em- 

 bryonic cell ; the two cells become four and multiply by endogenous 

 production of daughter-cells ; each mother-cell becomes an ovarian 

 tubule ; daughter-cells sometimes become mother-cells. The tubule 

 is formed by the aggregation of the protoplasm most abundantly 

 around the daughter-cell which is to lie at the distal end of the tubule ; 

 this cell grows rapidly and its protoplasm becomes granular; it 

 pushes outwards the cell-membranes of the mother-cell and itself 

 breaks up into daughter-cells, forming the first ovarian chamber ; a 

 similar process is repeated for the second chamber, and so on. The 

 excretory tube is formed from a primary mother-cell. The epithelium 

 of the ovarian tubules is homologous with the ova and the yolk-forming 

 cells. The muscles which unite the tubules are produced from small 

 cells which are developed from the remains of the protoplasmic matrix 

 out of which the primary mother-cells originate. The terminal 

 filaments of the tubules have the same structure as the tubules ; they 

 end cajcally, and may either be attached to other organs, or be united 

 by muscle-fibres, or end freely. 



In the larvae of Gecidomyia, the primary mother-cells do not form 

 ovarian tubes, but become free and pass into the body-cavity, forming 

 the " pseudova " of Leuckart, which are in reality sexual glands. 



Systematic Characters of the Labrum of Syrphidse.t — J. Gazag- 

 naire gives an account of the characters of the labrum in this group 

 of the Diptera, describing a special method of articulation, due to a 

 want of chitinization, which appears to characterize these forms, and 

 points out the generic differences which obtain between Ceria, 

 Eumerus, and Yolucella. The present series of studies is confined to 

 native forms, but the author's observations on exotic Diptera lead him 

 to believe that the characters indicated have a general significance. 



Genital Organs of the Orthoptera.t — A. Berlese, as briefly re- 

 ported, has studied species belonging to all the six families of this 

 order, taken in its restricted sense, viz. Mantidce, Locustidce, Gryllidce, 

 OryllotalpidcB, Truxalidce, Acrididca. 



Of the female organs, the ovipositor is made up of three pieces, 



* Zool. Anzeig., v. (1882) pp. 653-7. 



t Comptes Keudus, xcvi. (188.3) pp. 351-3. 



X Atti Accad. Lincei (Rome) Transunti, vi. (1882) pp. 201-3. 



