162 Dr. R. Leuckart on the Aseaual Reproduction 
fused among the Cecidomyia, and possibly occurs very generally 
in that group of flies. 
What I purpose communicating in the following pages is only 
suited to support this opinion, as it chiefly relates to a new case 
of the reproduction in question. 
The larvee on which I made my observations were found by me 
during the first days of the present year, in considerable numbers, 
under the bark of a half-dead apple-tree attacked by fungi. 
They most closely resembled the form observed by Pagenste- 
cher in the beet-root refuse, with which they agreed especially in 
the number (two) of stigmata, and in the presence of pomts on 
the ventral surface ; but, from the somewhat larger size and the 
much more slender form of the body of my larva, as also from 
some other smaller differences, I believe I must regard it for the 
present as the representative of a distinet species. 
Unfortunately I have not yet sueceeded m studying the entire 
developmental history of my larva. Almost all my larvae had 
very recently escaped from the dead envelopes of their parents 
(3 millims.), which lay sometimes singly, sometimes grouped toge- 
ther under the bark, or were still enclosed in them although otber- 
wise perfectly developed. The largest individuals that I found 
living measured about 2 millims.,nearly twice the length possessed 
by the animals on eseaping from the skin of their dead parents. 
The body-cavity of these larger individuals usually contained, be- 
sides a number of small germs, from three to five larger, elongate 
oval masses up to 0°28 millim. in length ; but, on closer examina- 
tion, these masses all proved to be eae an d sige Their contents 
were broken up into a granular substance, which gradually became 
darker towards the centre, and generally enclosed one or several 
oil-drops, sometimes of very considerable dimensions. 
The following communication, therefore, relates less to the em- 
bryonic development of the Cecidomyide larvee, the investigation 
of which I postpone to a more favourable season, than to the ques- 
tion of the origin and nature of the germs, which move about 
freely in the body- -cavity and become new larvee. 
I cannot, however, publish my investigations on this subject 
without mentioning the assistance which I was so fortunate as to 
receive inthem from M. Mecaznikoff of Charkow. The following 
pages probably conta but few facts which this talented young 
zoologist had not likewise observed, and which he was not about 
to publish. 
According to Wagner’s representation, the germs (Hmbryo- 
naltheile, Wagn.) are produced from the fatty body of the larva, 
the contents of this, with a simultaneous change in its appearance, 
becoming massed together in portions, and broken up into the 
form of round balls after the separation of its enveloping mem- 
