lyili 
duction, the fact is one so remarkable that I think I need not 
apologize for returning once more to the subject. It has been 
almost an axiom among entomologists that no larva possesses the 
power of reproduction ; and when therefore M. Wagner, Professor of 
Zoology at Kasan, announced that he had discovered a case of 
asexual reproduction in the larva of a fly belonging to the genus 
Cecidomyia, his statement was received with an astonishment bor- 
dering on incredulity. Indeed the Editors of the ‘ Zeitschrift fiir 
wissenschaftliche Zoologie,’ to whom Prof. Wagner had forwarded his 
memoir, kept it back for two years, because the statements made by 
him seemed to them almost incredible. These statements have now, 
however, been confirmed by other excellent observers, namely, Meinert, 
Pagenstecher, Leuckart and Von Siebold; and there seems no doubt 
about the main facts; namely, that the larve of certain flies continue, 
throughout the autumn and winter, to produce a series of successive 
generations of larvee, the last of which are finally developed into per- 
fect and sexually mature individuals. The females then, after copu- 
tion, lay eggs, and thus the cycle commences again. 
I say “ certain flies,” because it is now almost certain that the 
different observers have had different species under notice, and Prof. 
Wagner even believes that he has met with five distinct forms. 
Two only, however, have yet been obtained in a perfect state, one of 
which appears to have been bred both by Prof. Wagner and by M. 
Meinert, the other by M. Meinert alone. The first is a new species, 
which has received the name of Miastor Metraloas, and is most 
nearly allied to the genus Heteropeza, from which it is principally 
distinguished by the structure of the tarsus. The second is named 
by M. Meinert, Oligarces paradoxus. 
Wagner and Meinert believed that the young larve originated 
from the general fatty tissue, and before the appearance of any 
special generative organs. Pagenstecher first called this in question, 
and expressed his belief in the existence of a proper “ germ-stock” 
or ovary. Leuckart has clearly shown that this is the case, and that 
the early stages in the development of the pseudova, from which the 
secondary larvee are produced, are the same as in the production of 
an ordinary dipterous egg. I entirely agree with him when he says 
that “ Every one who is acquainted with the developmental history 
of insects, or who consults the existing observations on that subject 
by Stein, myself, Lubbock, Claus, and others, will agree with me 
when I assert that the germ-balls of our larvae, with their contents, 
