SECRETORY PRODUCT OF THE LATERAL OVIDUCTS OF BACULUM-THAII HAUS (PHASMIDA, PHASMATIDAE) AND ITS CHANGE DURING EGG TRANSIT

The secretory product elaborated by the epithelium of the lateral ovid ucts of Baculum thaii (Phasmida : Phasmatidae) gives rise, in the ovid uct lumen, to 2 main structural types: fibrils and granules. The ultra structural characteristics of the fibrils are uniform throughout the v arious oviductal zones in both the virgin and mated females. However, the organization of the granules is characteristic of a particular zon e, and sometimes different in the same zone, when virgins are compared with mated females. The fibrils accumulate on the chorion of newly ov ulated eggs to form a thick, compact sheath outside which the granules converge, undergo rapid and multiple fragmentation, and overlay the f ibrillar sheath in an orderly arrangement. The fibrillar and granular components give rise, in both virgin and mated females, to the formati on of a sclerotized sheath called extrachorion that is still present i n newly laid eggs. The probable role played by these 2 extrachorionic components in relation to the egg is discussed. (C) 1997 Elsevier Scie nce Ltd.