Contributions towards the Embryology and Anatomy of 

 Polistes pallipes. 



II. The Early History of the Cellular Elements of the Ovary. 



By 



Wm. S. Marshall 



(Madison, Wisc. U.S.A.). 



(From the Zoological Laboratory, llniversity of Berlin.) 

 With Plate XII— XIV. 



Thematerial for the following paper was obtained in the vicinity 

 of Madison, Wisconsin, U. S. A. The work was done in the Zoological 

 Laboratory of the University of Berlin whose director, Professor 

 F. E. Schulze, I desire to thank for extending to me the courtesies 

 of the laboratory. 



In gathering the material, the embryos, larvae and pupae were 

 removed from the cells of the nest after returning to the laboratory ; 

 but the mature wasps were caught in its vicinity after it was first 

 disturbed. The ovaries of all bnt the embryos and youngest larvae 

 were generally dissected out in the preserving fluid which was to be 

 used. A larva, for instance, would be pinned down in a small dish 

 containing weak Flemming's Solution ; it was then cut open and the 

 ovaries, being cut out, would be at once placed in the Solution in 

 the dish. From this they were quickly removed to a dish of Flemming 

 of the strength used in preserving them. The same was done with 

 most of the other Solutions. With Gilson's or Tower's it was found 

 much easier to see and remove the ovaries of larvae which were first 

 injected, (by means of a small hypodermic syringe), with the Solution 

 used. They were then thrown into a dissecting-dish filled with the 

 same fluid, allowed to remain here five or ten minutes, and then 

 opened; the ovaries were removed and placed in another dish of 

 fresh preserving fluid. 



The different preserving fluids used were Flemming's, weak and 



Zeitschrift f. wissensch. Zoologie. LXXXVI. Bd. • 12 



