Colitr. towardy the Embryology and x^natomy of Polistes pallipes. 175 



text-book. In most of the papers dealing with this subject one finds 

 that several insects have beeu the subject of the work and it is only 

 in recent papers Paulcke (25), Giardina (8), that one finds the work 

 restricted to a single species. As tlie present paper treats only of 

 a Single insect, it is thought best to omit a more general historical 

 account and review the principal papers dealing, especially histo- 

 logieally, with the oyaries of Hymenoptera. Lately more attention 

 has been given to cytological detail and we haye the papers of 

 Geünberg (12), WiELOwiEjSKi (32) and Gkoss (11) but especially those 

 by GiARDiXA (8 and 9). 



Several of the older papers treat of the ovary of the Hymenoptera, 

 but in them there is very little or nothing bearing on the present 

 work. Leydig i20), working with Osmia bicomis, nientions that the 

 terminal filament is filled with clear cells which have large round 

 nuclei. In the following part of the tubule, he found cells whose 

 nuclei contained nucleoli, distinguishing between these, and those with 

 a shigle nucleolus : these latter developed into the egg. Ludwig (23), 

 observed that in Megacliile fusca the egg sent a process up between 

 the nurse cells; also that the epithelial cells did not entirely divide 

 the egg and nurse Chambers into two separate parts but that an 

 opening was left between them. 



In 1866 two important papers appeared; one by Blochmann (3) 

 and the other by Stuhlmann (27). Blochmann (3) worked with 

 three Hymenoptera; Camponotus ligniperda^ Formica fusca and 

 Vespa vulgaris. He found that the three showed but slight variations 

 and his account is almost entirely restricted to the first species. His 

 account begins after the oöcytes are arranged, one behind the other, 

 in the middle of the tubule and were easily recognized by the greater 

 size of their nucleus and their darker staining cytoplasm. He found 

 the oöcyte nucleus large, without a nucleolus and with but little 

 chromatin ; it contained a central mass froni which Strands passed to 

 the nuclear membrane. Oöcytes, when a little older, begin to bud 

 and this process results in the formation of many small nuclei 

 »Nebenkerne«; these first appear as small vacuoles lying near the 

 nucleus. A little later small staining granules appear in them, they 

 grow and acquire a distinct membrane. The contained matter increases 

 and finally forms small nucleoli and fine threads. The »Nebenkerne« 

 increase in number and proportionately the regulär nucleus decreases. 

 In the regulär nucleus almost the entire contents stain; but in the 

 >Nebenkerne«, only the nucleolus and the Strands. Some of these 



12* 



