A Study of the follicular Epithelium from the Ovary 
of the Walking-Stick, Diapheromera femorata. 
By 
Wm. S. Marshall. 
With 1 figure in the text and plates XXXV and XXXVI. 
The secretory activity of the follicular epithelium in the iusect 
ovary has been known for some time, Stein (25), a majority of the 
papers on the histology of the ovary containing some meution of or 
contribution to the subject. By far the largest number of those who 
have added to this work have adopted the vievv, that in those inseet 
ovaries in whicli food chambers are absent, the epithelial cells sur- 
rouuding the oöcyte play a large part in its growth. Besides the 
nourishment of the oöcyte the epithelial cells have also, as one of 
their functions, the secretion of the chorion, and, it has been held, 
Leydig (16), that this is, in a secretory line, their only activity. 
The papers in whicli one finds reference to this subject are, in 
general, those on the anatomy and the histology of the iusect ovary 
or, Mollison (20), whicli have to do entirely with the part played 
in the nourishment and growth of the oöcyte by the follicular epi- 
thelium. In this last mentioned work an historical review, bringing 
the subject up to 1904, is given and tkere is no need of here repea- 
ting what can be found in Mollisox’s paper. Siuce 1904, there 
have been other papers on the anatomy and histology of the ovarian 
tubules of insects: Daiber (6), Gross (10), Wielowejski (27); but 
none of these oppose the view that the epithelial cells have to do 
with the growth of the oöcytes. 
