DEVELOPMENT OF THE GENERATIVE ORGANS. 685 
the dorsal region on either side of the median line at a very 
early period of development, in the form of a pair of minute 
pyriform or reniform corpuscles composed of embryonic cells, 
each of which is connected with the hypodermis, on the ventral 
surface in front of the eighth abdominal segment, by a long fine 
cellular cord, the genital cord. Herold [140] and Suckow [839] 
discovered the differentiated rudiments of the sexual glands 
in the caterpillars of the Lepidoptera; and. Herold found dis- 
tinctly differentiated ovaries or testes in caterpillars which had 
only escaped from the egg a few hours, and concluded from 
this that the organs must be present in the embryo. Suckow 
[339] states that he actually saw the gonads in the embryo 
stage of Bombyx pini by the aid of a lens(?). He says ‘ The 
first appearance of the sexual organs is, in the earliest stage 
of embryonic life, as a bud from the alimentary canal, which 
at a later stage is divided into two lateral halves by a fissure 
extending from the alimentary canal and forms two hollow 
threads. Towards the latter end of embryonic life the rudi- 
ment of the sexual organ is separated from the alimentary 
canal as a bulb at the anterior end of the two threads.’ These 
observations of Suckow’s are exceedingly imperfect, and do 
not agree with more recent investigations; he evidently mis- 
took the rudiments of the oviducts and bursa for the sexual 
organs, and his description of these is inaccurate. 
Brandt [830] rejected Suckow’s views as erroneous, and says 
349, KORSCHELT, E., ‘ Ueber einige interessante Vorginge bei der Bildung 
der Insecteneiern.’ Zeitsch. f. w. Zool., Bd. xlv., 1887. 
350. HENKING, H., ‘ Die ersten Entwicklungsvorgiinge in Fliegenei und 
freie Kernbildung.’ Zeitsch, f. w. Zool., Bd. xlvi., 1888. 
351. JACKSON, W. HATCHETT, ‘Studies in the Morphology of the Lepi- 
doptera.’ Trans. Linn. Soc., Lond., vol. v., 1890. 
352. RirrerR, R. von, ‘Die Entwickelung der Geschlechtsorgane und des 
Darmes bei Chironomus.’ Zeitsch. f. w. Zool., Bd. 1., 1890. 
353. PouLTon, E. B., ‘The External Morphology of the Lepidopterous 
Pupa, its relation to that of other stages, and to the origin and history 
~ of Metamorphosis.’ Trans. Linn. Soc., Lond., vol. v., 1890-1891. 
354. Hrymons, R., ‘Die Entwicklung der weiblichen Geschlechtsorgane 
von Phyllodromia (Blatta) Germanica.’ Zeitsch. f. w. Zool., Bd. liii., 
1891. 
