ME. LUBBOCK ON THE OVA AND PSEUDOVA OE INSECTS. 
355 
like a cucumber. It consists of a large number of egg-tubes, each formed of two 
chambers, one more or less spherical, and the other a miniature representation of the 
ovary itself, as far as shape is concerned. 
The external membrane is in this species very distinct, and the internal structure ot 
the egg-tube cannot distinctly be seen until it has been removed. It is, however, easily 
torn off, and the egg-tube will then be generally found attached by the upper part, and 
with the end next to the spherical chamber floating loose. The part of the egg-tube 
also below the spherical chamber is very thin, and tapers rapidly to a very delicate 
filament, while the upper part retains to the end a much more considerable diameter. 
These facts puzzled me a little at first, and made me doubt for awhile which was the 
ovarian end of the egg-duct. I soon found, however, that the germinal vesicle was 
always at the side of the egg-germ which was turned away from the cylindrical cham- 
ber ; and a specimen occurred in which the lower part of the cylindrical chamber was 
beginning to separate itself from the remainder, and to form a new egg-germ (Plate 
XVII. flg. 8). Towards the middle of October, all, or nearly all the egg-tubes were in 
this stage. The vitelligenous cells contained no distinct nucleus, and varied much in 
size, some being larger, and others smaller than the egg-cell. 
In the Geodephaga and Hydradephaga, Stein has already observed that we find a type 
of egg-formation differing enthely from that of the other Coleoptera, and closely resem- 
bling that of the Hymenoptera, from which indeed it only differs (so far as our know- 
ledge at present extends) in possessing a, terminal germ-chamber. 
This terminal germ-chamber is, however, less largely developed in the present group 
than in most other Coleoptera, and in old specimens, indeed, is very much reduced in 
size. 
Plate XVII. fig. I represents one of the egg-tubes of Carahus violaceus, magnified 
thirty times. At the lower or posterior end was a glandular part containing a yellow 
mass, which Stein, apparently with justice, considers as analogous with the “ corpus 
luteum.” The lowest egg-chamber was very opake, so that no structure could be per- 
ceived in it. In the second or penultimate egg-chamber, and the two following, the con- 
striction separating the germ-chamber from the yelk-chamber is well marked ; the three 
following have a constriction separating them from one another, but the chambers them- 
selves have an entire margin ; and still nearer to the end are several egg-germs, which 
are not sufficiently large to occupy the whole diameter of the egg-tube. 
Plate XVIII. fig. 18^ represents a germinal vesicle oi Pterostichus melanarius. In this 
specimen the macula germinativa contains five large equal-sized vesicles. I have found 
other specimens presenting very nearly the game appearance, but it is by no means usual, 
and was not present in two other germinal vesicles belonging to the same egg-tube. In 
the smallest of these (Plate XVIII. fig. 18^), the germinal vesicle contained two small 
equal-sized vesicles. In the second (Plate XVIII. fig. 18^), the germinal vesicle con- 
tained three vesicles, one rather large and the other two smaller. 
The vitelligenous cells present nearly the same appearance as in the egg-tube of a 
