582 



The mature egg is a light green, ovate mass about -^^ in length 

 and yfnn) in breadth, and possesses apparently only one envelope. 

 It contains a well-formed embryo before it leaves the ovary, and is 

 hatched, I believe, only a few hours after being laid. According to 

 M. Leydig, the first trace of the embryo arises at the free or cephalic 

 end, but my observations have led me to the opposite conclusion. 



C. persicce differs from C. hesperidum in being decidedly oviparous ; 

 that is to say, the eggs, when deposited, do not contain an embryo, 

 and remain under the protection of the mother some time before 

 being hatched. This difference probably makes tehm require a 

 stronger egg-shell, and accordingly we find the collateral glands 

 more developed. In most respects, however, the egg-development 

 is very similar in these two species, but the egg- follicles are smaller and 

 neater in C. persicce than in the former species, and the vitelligenous 

 cells are five or seven in number instead of three, spherical and very 

 distinct. 



In Cynips lignicola, the ovary consists of a number of egg-tubes 

 which fall into a common oviduct, and each of which contains 

 thirteen eggs. 



This species has in the last few years become very common in the 

 South-west of England, but as yet only females have been discovered. 



It is fair to assume, therefore, that the eggs are agamic, or adopting 

 Prof. Huxley's name, pseudova. Nevertheless, there is absolutely 

 nothing, so far as our knowledge at present extends, to distinguish 

 the egg-formation from that which occurs in any other Hymenopterous 

 insect. 



The mature egg of Cynips is indeed of a very remarkable shape, 

 as it consists of a long tube with a small swelling at one end, and a 

 larger one at the other, in which the yolk is situated. 



The larger end occupies the usual place of the egg, but as the tube 

 elongates, the smaller end pushes its way up the egg- tube, which 

 elongates considerably ; and, finally, all the large ends are at the lower 

 end, and the small ones at the upper end, of the egg-tube, which 

 gives the ovary a curious appearance. Even after the egg is fully 

 formed, a slight pressure will bring the germinal vesicle into view. 



Many of the Lepidoptera have presented us with cases of Parthe- 

 nogenesis, and in these instances there is no reason to suppose that 

 the formation of the eggs differs from the usual type. The same 



