170 Dr. R. Leuckart on the Asexual Reproduction 
stance that it exhibited a clear band along one of its sides, which 
I am the more inclined to regard as a residue of the primitive 
band, because it sometimes had a repeatedly undulated course, 
as if a division into so-called primitive segments had already 
taken place. These were stages which might correspond with 
fig. 33 of Wagner’s memoir. 
Wagner's statement that the embryo is developed, not in the 
periphery, but m the interior of the yelk, is undoubtedly an 
error, probably induced only by the incomplete analysis of the 
parts situated in the interior of the germ-chamber. What 
Wagner calls the peripheral yelk is probal oly nothing but the 
epithelium of the germ-chamber, or the granular layer proceed- 
fo) 
ing therefrom, of which mention has already been made, in the 
ro) 
periphery of the germinal membrane. The “segmentation ” 
figured by Wagner (fig. 82) also evidently pertains to this epi- 
thelial layer, and might possibly serve as evidence that, as above 
surmised, its cells in “the normal state persist much longer than 
I observed them in my specimens. 
Imperfect as are my observations upon the fate of the Ceci- 
domyide germs, they enable us at least to assert that the pro- 
cesses of embryo-formation agree in all essential points with the 
ordinary phenomena of development in a fecundated egg, ex- 
actly as has been proved (by Huxley) to be the case in the 
Aphides. 
According to the preceding investigations, the asexual propa- 
gation of the Cecidomyie unmistakeably approaches the*pheno- 
mena long known to take place in the Aphides (since the time 
of De Geer and Réaumur). The only difference consists in the 
germ-chambers of the Cecidomyide larvee separating from the 
germ-stock, and moving about freely in the cavity of the body, 
whilst in the dphides they remam permanently attached, and 
constitute an apparatus which, in its form and arrangement, 
reproduces the conditions of the female organs. 
That the germ-stock of the Cecidomyide larvee likewise pre- 
sents us with an analogue of the sexual glands seems to be the 
less doubtful, because we find it precisely on the spot where we 
should expect the first traces of these structures, and see it in a 
form which is at first very generally proper to the sexual glands 
in Insects. The appendicular filament running backward is 
evidently to be regarded as a rudimentary efferent duct. 
Hence the asexual reproduction of the Cecidomyide larvee 
not only shows a close agreement with the similar reproduction 
of the Aphides, but even approaches much more closely to 
sexual reproduction than previously appeared to be the case. 
The germ-stock of the viviparous larvee is to a certain extent a 
second tonal af sexual apparatus ; and its reproductive bodies so 
