528 ROBERT W. HEGNER 
Text fig. A | Microphotographs of longitudinal sections through the abdomen 
of Apanteles showing various stages in the growth of the oocytes. The germ- 
line determinants appear as distinct triangular black bodies near the posterior 
ends of certain of the larger oocytes. 
up into a large number of irregular masses, suspended in a 
homogeneous substance. Near the germ-line-determinant in 
later stages (fig. 75) are a number of large widely scattered 
granules which are probably separated off from-:the main body. 
The resemblance between this body and the pole-plasm in the 
egg of Miastor (Kahle ’08; Hegner °12, ’14a, ’14¢c) is quite 
striking. The pole-plasm in Miastor appears just before the 
oocyte undergoes maturation, and apparently does not arise 
directly from the germinal vesicle, nurse cells, or follicular epithe- 
lium, but is a visibly differentiated portion of the cytoplasm that 
has become localized at the posterior end. What causes this 
differentiation is not known, but a discussion of the subject will 
be found in my previous contributions (Hegner 714 a, 714 ¢). 
In Miastor the pole-plasm never proceeds beyond the granular 
stage, but in Apanteles a rather definite series of conditions 
