120 BRITISH APHIDES. 



The number of these ovarian chambers varies with 

 the genus and species of Aphis. As a rule, the chambers 

 composing the ovaries of the true female are less 

 numerous than the pseudovarian cysts of the viviparous 

 insect. 



In Chermes, however, the ovarian cysts are very 

 numerous during the summer : as many as ninety or 

 one hundred may be counted in one individual. In 

 respect to such species as only elaborate a single egg y 

 the corresponding organs are more simple in form. 



Just as with the agamic winged females, these 

 chambers communicate one with another, so as to form 

 many distinct branches; and these branches again unite 

 so as to form two fasciculi, each ending in their 

 respective oviduct. 



Early in October Mr. Foran kindly forwarded to me 

 several specimens of the oviparous female of Cal- 

 li'ptenis quercus, taken on the oaks near Eastbourne. 

 They were of a bright yellow colour ; and similar ones 

 have been figured on Plate XC, fig. 3, Vol. Ill, of this 

 Monograph. 



They differed much as to the number of forward 

 eggs within ; for some specimens contained ten, twelve, 

 thirteen, twenty, and thirty-eight eggs respectively. 

 Some eggs were yellow, whilst others were of different 

 shades up to black. Balbiani thinks this change of 

 colour does not take place until the eggs be fecundated. 

 However this may be, all shades of colour may be 

 traced in the unimpregnated pseudo-eggs of Chermes. 

 It is difficult to speak with certainty as to the exact 

 number of branches which arise from the fasciculi 

 of different species. In genera like Pemphigus the 

 reproductive organ must be very simple, since it gives 

 rise only to a single egg of great size. On the con- 

 trary, the fact that thirty or more eggs may be seen 

 in one female of Callijpterus quercds leads to the sup- 

 position that each fascicle in this species contains five 

 or six brauches. In the figure given in PI. F, fig. 3, six 

 branches are drawn as seen from the camera; but 



