Mr. J. Lubbock on the Ova and Pseudovn of Imecfs. 505 



of any ordinary insect, in consisting of an upper chamber containing 

 the vitelligenous cells, and a lower chamber devoted to the germinal 

 vesicle and the yolk. 



According to M. Leydig, the constriction gradually disappears, 

 and the egg finally occupies both chambers ; but this is incorrect, and 

 M. Leuckart is right in asserting that the vitelligenous cells dis- 

 appear, and the upper chamber becomes atrophied, so that the mature 

 egg lies in the lower chamber only. This process is exactly that 

 which the analogy of other insects would lead us to expect. 



The general cavity of the body of the female Coccus always con- 

 tains an immense number of oval green cells, apparently of a parasitic 

 nature. They are y-^,Vo bi length, and vary in breadth, but on an 

 average are about ^tcmTo • Coccus Persicce contains a number of similar 

 bodies, which however are cylindrical. Almost always, immediately 

 after the disappearance of the vitelligenous cells, two or three masses 

 of these cells may be found at the lower part of the upper chamber, 

 and soon after in the egg itself. It is difficult to understand why these 

 cells should ap])ear at so definite a period in the history of the egg- 

 formation. Prof. Huxley has pointed out to me that Dr. V. Wittich 

 has already descril)ed a Conferva found in hen's eggs. It does not, 

 however, seem clear that these eggs would have arrived at maturity, 

 and I believe that the parasites of Coccus are the first which have ever 

 been known to exist in eggs without impeding their development. 



The mature egg contains numerous vitelline spherules, which are 

 from ^,0^ to -j^o in diameter, and offer every appearance of true 

 cells, except that they contain no nucleus. 



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

 and TT-^f^,-, 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 0})p03ite conclusion. 



C.PersiccB 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 them 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 adoi)ting 

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

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



