ON THE AGAMIC REPRODUCTION AND MORPHOLOGY OF APHIS 49 
senting a yelk, are set free as pseudova, and are then undistinguishable 
from true ova. 
6. The pseudova are eventually converted into cellular germs, 
apparently by the same process as that by which an ovum is converted 
into an embryo. 
7. In these germs the central part becomes a granular pseudo- 
vitellus, the peripheral a blastoderm ; the rudiments of the different 
organs next appear, and the germ becomes surrounded by a pseudo- 
vitelline membrane. 
8. Eventually the pseudovitellus probably becomes the corpus 
adiposum. 
g. All the other organs are developed from the blastoderm, which 
becomes distinguished into two layers. From the outer of these the 
muscles, nerves, limbs, and tegument are developed, while the inner 
gives rise to a part of the alimentary canal (?) and to the reproductive 
organs or pseudovarium of the larva. 
10. The pseudovarium contains no particle of unchanged tissue of 
the germ, but is a considerably differentiated and readily distinguish- 
able mass. The mass divides into ten lobes anteriorly ; and these 
lobes become the pseudovarian ceca. Before the larva is born, each 
cecum is divided into three chambers, the two posterior of which 
contain rudimentary embryos. 
11. The genital apparatus of the oviparous female consists of a 
vagina, oviducts, and ovarian ceca. The latter are multilocular ; and 
the vagina is provided with the spermatheca, and the two colleterial 
glands first demonstrated by Von Siebold. 
12. The rudiments of the ova are undistinguishable from those of 
the pseudova. They are developed in the lower part of the apical 
ovarian chamber, the upper part of which is occupied by the bodies I 
have termed ovarian glands. The ova are not at first enveloped in a 
chorion. 
13. In the lowest chamber the ova are provided with a chorion, 
vitelline membrane, and what appears to be a micropyle. 
If these propositions are correct, I see no valid objection to the 
conclusion, that the agamic offspring of Apfzs is developed from a 
body of precisely the same character as that which gives rise to the 
true egg. The pseudovum is detached from the pseudovarium in the 
same way as the ovum from the ovarium. In both cases, the act of 
separation is in every respect a process of gemmation. 
From this point onwards, however, the fate of the pseudovum is 
different from that of the ovum. The former begins at once to be 
converted into the germ; the latter accumulates yelk-substance, and 
E 
