of Cecidomyide Larve. 171 
completely correspond with eggs, as regards their general mor- 
phological relations, that we might, with a certain amount of 
justice, regard them as a second form of eggs, as, indeed, Claus 
has recently done in the case of the Aphides. In all probability, 
the larvee of the sexually mature Cecidomyia, at the first appear- 
ance of the genitalia, present so little difference from the earlier 
states of the viviparous larve, that it might be supposed that 
the subsequent fate of those organs, and at the same time that 
of the animal to which they belong, may be determined, as in 
the Aphides, by certain external conditions—in other words, 
that it may depend upon certain external conditions whether the 
larva shall be developed into a sexual animal or a viviparous 
individual. 
With every inclination to recognize the morphological relations 
to eggs presented by the reproductive bodies in the detached 
germ-chambers of the Cecidomyiea, I cannot quite determine to 
describe them as eggs and thus characterize the reproduction 
of the Cecidomyide larvee as a parthenogenesis. Just as the 
larval forms of an animal cannot be placed on the same level as 
the fully developed creatures, and regarded as such, so we must 
not transfer the denomination “eggs” to structures which have 
only their first stages of development in common with eggs. 
The existence of an egg in all cases presupposes sexual maturity; 
but our larve are (much more strikingly than the viviparous 
Aphides) marked out as immature animals by their develop- 
mental form, and, from the condition of their genitalia (their 
conversion into germ-stocks), are to be described as sexually 
indifferent, or rather as asexual. 
An egg, according to the ordinary conception of its conditions, 
must, at least in its structure, present the possibility of fecunda- 
tion; where this possibility is absolutely wanting, we have cer- 
tamly not to do with an egg, but rather with an asexual repro- 
ductive body. 
Hitherto we have been accustomed to characterize structures 
of this kind, produced freely in the body of the parent, as germ- 
grains or spores, in opposition to eggs; if this name be regarded 
as inapplicable in the present case (as in that of the Aphides), 
from its being too general and morphologically unmeaning 
(farblos), the name pscudovum might perhaps be recommended 
for adoption—a name which has been employed by Huxley, 
although certainly in a different and scarcely justifiable manner 
(for the true eggs which are capable of spontaneous develop- 
ment). 
After the preceding statements, I need scarcely state expressly 
that in the reproductive history of the Cecidomyie I see a case 
of alternation of generations, approaching in the closest manner 
