348 
ME. LUBBOCK ON THE OVA AND PSEUDOVA OF INSECTS. 
Dr. Leydig'*, in Ms paper on the Agamic Eeprodnction of Aphis, and Professor 
Huxley (/. c. pi. 36) have figured in the terminal chamber certain round, nucleated cells, 
any one of which may develope itself into a germinal vesicle, and so pass down the tube 
and form around itself the future egg. These so-called cells are probably homologous 
with the nuclei of the vitelligenous cells. 
Dr. Lbydig also, in his paper on Coccus hesperidum, figures certain large nucleated 
cells in the upper chamber of the short egg-tubes, but having overlooked the true 
germmal vesicle, he seems to have (if I understand him right) considered these bodies 
as the equivalents of the germinal vesicle, whereas in fact they are true vitelhgenous 
cells, differing neither in position nor appearance from the t}q)e present in the other 
Homoptera. 
Professor Leuceaet also [1. c.) has described these cells \n Aphis, Coccus, ondi Solenohia 
lichenella, and adopts in reference to them the same opimon as Professors Steix and 
Huxley. 
In adopting the term “ vitelligenous ” as applicable to these bodies, I have expressed 
my opinion of their function ; an opinion, I may add, which was adopted independently 
by Professor Stein, Professor Huxley, and myself. In proof of this Mew I would refer 
to the egg-tubes of any Lepidopterous or Hymenopterous insect, or to Hekold’s figs. 15, 
16, 14, 13 and 12 {1. c. pi. 1). It will there be seen that although the MteUigenous cells 
increase individually in size, as does the yelk-mass, yet that the latter constantly grows 
at the expense of the former, which become fewer in number, and fixially disappear 
altogether. 
Professor Stein has observed that in Acilius sulcatus, in which the yelk is brightly 
coloured, the vitelligenous cells are of the same hue ; and in all bisects the contents of 
these cells closely resemble the mass of yelk substance. 
Professor Huxley has observed in Aphis, and I have noticed in certain Hemiptera 
(see Plate XVII. figs. 7 and 9), that a tube, or channel, leads dorvn fi-om the terminal 
chamber into the second and thbd egg-chambers, which seems eMdently intended to 
convey the yelk-matter to the developing eggs. 
Finally, if, as Professor Stein also remarks, we press the Mtelligenous cells out of one 
of the egg-chambers, we shall generally find some of them in which the cell-wall is 
almost entirely absorbed, so that on the application of but slight pressui'e the contents 
spread in all directions. 
The two theories respecting the nature of these cells are not quite so opposite to one 
another as would at first sight appear to be the case. In theb earliest stage the egg- 
cell and the vitelligenous cells cannot be distinguished from one another ; and no one, I 
think, who has carefully examined the upper part of the egg-tube in any Hemipterous 
or Dipterous insect, can fail to be of the same opinion. The egg-tube contains indeed 
at this end cells which are neither vitelligenous nor egg-cells, but which are capable of 
becoming under certain circumstances either the one or the other. 
* Zeitsckrift fur Wissenscliaftliche Zoologie, 1849, pi. 5. 
