1 06 M. Oscar von Grimm on the Agamic Reproduction 



XIII. — On the Agamic Reproduction of a Species 0/ Chiro- 

 nomus, and its Development from the TJnfecundated Egg. 

 By Oscar von Geimm. 



[Concluded from p. 45.] 



III. The Development of the Embryo in the TJnfecundated 



Ovum. 



The embryonic development of Chironomus in the fertilized 

 ovum has already frequently been investigated and described 

 by various observers, such as Kolliker, Kupfer, Weismann, 

 Metschnikow*, and Melnikow ; but the development from the 

 unfecundated ovum, as, indeed, even the ovum itself, has 

 hitherto been unknown. 



We shall see hereafter that the development of the embryo 

 from the fecundated and unfecundated ovum perfectly agrees, 

 so that we might content ourselves with describing the points 

 of divergence between our investigations and those of other 

 observers, if it were not that we intended publishing a more 

 detailed memoir on the development of the histological ele- 

 ments and organs. But, as I have already made some inves- 

 tigations in this direction, and will, as soon as possible, lay 

 the results of this work before the reader, I regard it as neces- 

 sary to give here a short summary of the course of development, 

 especially as, in some cases, I have arrived at different results 

 from Weismann, who, however, has most completely investi- 

 gated the embryology of Chironomus. 



I must, however, remark that I shall here rarely refer to 

 authors, as I regard this chapter as a preface to my future 

 work. 



As we already know that in Chironomus the second, 

 asexually produced generation is developed from ova, we need 

 not discuss the opinion of Wagner f and Meinert J upon the 

 genesis of the Cecidomyid larvse from the fatty body of the 

 parent larva (to which, moreover, Meinert ascribes pecuHar pro- 

 perties), since the supposition of Pagenstecher§ that the larvae 

 originate independently of the fatty body has been proved by 



* Prof. Metschnikow's most recent investigation upon the embryology 

 of Chironomus is imfortunately only partially known to me, as it is not 

 yet published. 



t "Beitrag zur Lehre von der Fortpflanzung der Insectenlarven," 

 Zeitschr. fiir wiss. Zool. 1863, Bd. xiii. p. 522. 



X ** Weitere Erlauterungen iiber die von Prof. Wagner beschriebene 

 Insectenlarve," &c. Zeitschr. fiir wiss. Zool. Bd. xiv. p. 395. 



§ " Die ungeschlechtliche Vermehrung der Fliegenlarpen," Zeitschr. 

 fiir wiss. Zool. Bd. xiv. p. 410. 



