178 
J. BRONTE GATENBY. 
Germ Cell and Determinant. 
In the ordinary Hymenopterous larva (e.g. Vespa) the 
germ cells lie about two-thirds way in the length of the body 
and above and resting upon the mid-gut. 
In the Tricliogramma larva the germ cells are situated at 
the posterior pole and ventral to the proctodasum. In the adult 
insect the ovaries occupy the same position as they do in the 
Vespa imago. Migration of germ cells is very small in the 
developing embryo. In most insect embryos the germ cells 
.are carried into the tail fold, and may be said to either 
migrate or be passively carried a good distance, but except 
for the early insinking of the germ cells and the formation of 
the germ pocket in Tricliogramma the position of these cells 
is hardly altered. 
I have looked carefully at my sections of the adult ovary, 
and find that the germ cell determinant appears as a cloud of 
granules, which become more and more heavily staining, and 
denser and denser, until the determinant resembles a dark 
spherical ball at the posterior pole of the egg. The whole 
history of the germ cell determinant, in so far as the 
ovary is concerned, has been exhaustively treated by 
Hegner (3) in more suitable insects. I have examined a 
number of sections of the Hymenopterous parasites common 
on Aphids, and I am able to substantiate most of his remarks ; 
but in the nurse cells, as well as in the developing oocyte, 1 
have found curious large spherical granules which have not 
hitherto been mentioned. These seem to appear after 
synezesis in the oocyte, and whether they have anything to 
do with the germ cell determinant I cannot at present say. 
If suitable material is procured I hope to examine this 
point. 
Addendum. 
When this work had been finished I had not had the 
opportunity of acquainting myself with Prof. Silvestri’s 
writings, only knowing of them through short reviews in 
