of Cecidomyide Larve. 167 
Every one whois acquainted with the developmental history 
of insects, or who consults the existing observations on that sub- 
ject by Stein*, myselft+, Lubbock t, Claus§, and others, will agree 
with me when Lassert that the ¢ germ-balls of our larvee with their 
contents precisely reproduce the conditions of one of the so-called 
germ-chambers from the ovarian tubes of a female insect. This 
is perhaps most striking on comparison with Melophagus||, the 
germ-chambers of which are united to each other ouly by a thin 
cord, and consequently represent structures almost as indepen- 
dent as the germ-balls of our Cecidomyie. 
In both cases we have a structureless proper membrane, con- 
taining in its interior, besides an epithelial layer, two different 
kinds of cell-formations. One of these cell-forms is present only 
singly, and situated at the originally narrower pole of the germ- 
chamber. It is the future Ga, which consists of a eranular ball, 
constantly increasing im size, and a vesicular riiiClORSs the so- 
called verminal [cael wiles the other cells, which, with their 
likewise vesicular nuclei and often incompletely discriminated 
protoplasm, fill all the rest of the interior space of the chamber 
aud play a part in the separation of the yelk, are usually described 
as formative cells of the vitellus4. 
The agreement of the germ-balls with egg- chambers is so com- 
plete, that it applies not only to the later. stages, but also to the 
development, as is sufficiently proved by the accurate investi- 
vations of Claus, which I can fully confirm. The egg, the 
formative cells of the vitellus, and the epithelial cells, indeed 
everything is developed 1 in the ovarian chambers exactly i in the 
same way as is described above for the germ-balls, by differenti- 
ation from an originally quite homogenous cell-mass. liven as 
regards time these processes present precisely the same conditions 
in both structures. 
The germ-balls of the Cecidomyide larve are therefore neither 
“embryonal particles” (Hmbryonaltheile, Wagner) nor “ova” 
(Pagenstecher), but germ-chambers which produce a reproductive 
* Vergl. Anat. und Physiol. der Insekten, 1847, p. 46. 
+ Art. “ Zeugung,” in Wagner’s Handworterbuch, Bd. iv. 1852, p. 802; 
Zur Fortpflanzung und Entwickelung der Pupiparen, 1859; Zur Kennt- 
niss des Generationswechsels und der Parthenogenesis bei fen Insekten, 
1858, p. 48. 
~ “On the Ova and Pseudova of Insects,”? Linn. Trans. 1859. 
§ ** Beobachtungen iiber die Bildung des Insekteneies,”’ Zeitschr. fiir 
wiss. Zool. Bd. xiv. p. 42. 
|| Leuckart, Fortpflanzung der Pupiparen, taf. 1. figs. 6 & 7. 
q Weienune (Entwickelung der Dipteren. p. 208) is decidedly in error 
when he denies, in Musca, the: distinction between the egg and the forma- 
tive cells of the vitellus, and represents the entire contents of the germ- 
chamber, with its many nuclei, as passing directly into the egg. 
