154 Proceedings of the Royal Society of Edinburgh. 
[Sess. 
XV. — 1 The Formation of the Germ-Band in the Egg of the Holly 
Tortrix Moth, Eudemis nsevana (Hb.). By L. H. Huie, F.E.S. 
Communicated by J. H. Ashworth, D.Sc., F.R.S. From the 
Department of Invertebrate Zoology, University of Edinburgh. 
(With Two Plates.) 
(MS. received June 3, 1918. Read June 3, 1918.) 
Introductory. 
During the spring of 1916, while making observations from an economic 
point of view on the Holly Tortrix Moth, Eudemis ncevana (Hb.), I found 
that, owing to the transparency of the egg and its flattened form, the 
development could be followed in the living egg in a general way with 
unusual clearness. 
Investigations have been carried out on the embryology of about 
eighteen species of Lepidoptera, but as far as I am aware no account has 
been published of the embryology of the Tortricid8e. The early stages 
of Bombyx mori and Pieris cratcegi have been investigated by several 
different observers, but, for one reason or another, the details of the 
formation of the germ-band from the primitive ventral plate have remained 
obscure. The present investigation was undertaken with the object of 
clearing up some of these obscure points on the more favourable material 
at my disposal. 
The ventral plate, the earliest indication of the embryo in the 
Insecta, originates in an area of the blastoderm on the ventral side of the egg, 
which becomes marked off by its cells assuming the form of a close columnar 
epithelium, while in the remaining portion of the blastoderm the cells become 
flattened. Accounts vary as to the shape of the ventral plate in those 
Lepidoptera in which it has previously been described. Herold describes 
it in the egg of Sphinx ocellata as a flat-sided figure with rounded corners. 
Kowalevsky figures the ventral plate of Sphinx populi as somewhat spade- 
shaped. Tichomiroff figures and describes that of Bombyx mori as four- 
sided, with a notched head end. Graber depicts as nearly circular the 
ventral plate of Pieris cratcegi, which Bobretzky had figured as an oval 
with enlarged ends, its long axis being transverse to the long axis of the 
egg. Bruce, who studied the embryology of Thyridopteryx ephem ercef or mis. 
