﻿Contr. toward the Embryol. and Anat. of Pol. pallipes (Hymenopt.). 137 



cm the connecting fibres in Steropus which differ, however, from 

 those we find in being much thinner and longer. That which, as 

 far as we can ascertain, approaches nearest to the condition we find 

 in Polistes occurs on the connecting fibres of dividing cartilage cells 

 figured by Schleicher (50), although he has represented the thicken- 

 ings as occurring regularly, a condition not fonnd by us. Another 

 peculiarity we wish to mention was the occurrence in some dividing 

 nuclei of one or more large irregulär bodies found most frequently 

 surrounded by the connecting fibres (Figs. 20 and 21), but which were 

 also seen just outside of them (Fig. 23). As many as five of these 

 peculiar bodies were seen together, the number two or three being, 

 however, much more prevalent. They were of a light brown color, 

 failed in any of our preparation to stain, and occurred oftener in 

 the mitosis of the yolk nuclei. 



After the divergence of the chromosomes is completed the centro- 

 some, archoplasm and astral fibres can yet be seen. When the 

 nuclear membrane Starts to form, the astral fibres begin first to 

 disappear, followed by the centrosome and archoplasm, the last 

 disappearing somewhat later than either of the others. Even after 

 the nuclear membrane can be distinguished , a small mass of 

 archoplasm is often discernable (Fig. 25). After completed mitosis 

 the resultant nuclei are small, less than one -half the size of the 

 nucleus before division; they apparently increase rapidly in size, 

 very few of the smaller ones being seen. Just previous to, and 

 often after, the formation of the nuclear membrane, connecting fibres 

 are distinctly seen (Fig. 25). The same thing has been figured by 

 Lecaillon (35) where, after the mitosis is completed, in the egg of 

 Clythra, and the nuclear membranes formed, connecting fibres still 

 remain. 



We have shown that in the egg of Polistes the nuclei arrange 

 themselves into two groups and, either resting or dividing, are similar 

 to each other, their only difference being their -position within the 

 egg. The inner group, the yolk nuclei, lie scattered irregularly 

 throughout the greater part of the egg ; the other group, the cleavage 

 nuclei, have arranged themselves in a zone which is at nearly all 

 parts equidistant from the eggs surface. On the surface of the egg, 

 just within the membranes, lies the Keimhautblastem. The nuclei 

 forming the zone increase their number by mitosis and gradually 

 approach the surface. The last stage we have described was one 

 in which the cleavage nuclei were near the surface of the egg. We 



