354 
CHESS WELL SHEARER. 
the manner we have just seen, then the germ-cells of a female 
in which early fertilisation has been prevented, by the cutting 
out of the males in an early segmentation stage, should show 
only one of them within the nuclear membrane. Although 
this operation of cutting out of the males is a difficult one to 
accomplish, as I have fully explained, in the Introduction, in 
the few instances, in which I have succeeded, the oogonial 
cells of these females on development only showed one pro- 
nucleus, and are quite different from the ordinary oogonial 
cells with their two darkly staining masses of chromatin in 
each compartment of the nucleus. In Text-fig. 5 a drawing is 
shown of the germ-cells of such a female. The small oogonial 
cells in this figure, which is taken also from an aceto-carmine 
preparation, are about the same size as those shown under 
greater magnification in fig. 24. In fig. 24 the male and 
female portion of the nucleus show quite distinctly, while in 
Text-fig. 5a and b, the male portion, the sperm head is not 
present. In all the oogonial cells in which the sperms have 
been prevented from entering, we find therefore that the 
nucleus consists of one single compartment, with one chromatic 
body. The double character shown by|the nuclei of the 
fertilised oogonial cell does not appear. In rearing these 
females, moreover, it is clear almost from the first that the 
conditions of growth are very materially altered. Their germ- 
cells appear much later than in the normal state, and grow 
very slowly, or hardly at all. In this particular instance they 
took over a month to attain the size shown in this drawing; 
in a normally fertilised female they would attain this size in 
a week’s time. 
I have stated in the Introduction that I am still doubtful 
as to whether females, in which early fertilisation has been pre- 
vented, can really be raised to the adult condition, that is to 
a stage when they lay eggs. While I think I have succeeded 
in one or two instances, I am by no means absolutely certain 
that 1 did avoid fertilisation in these instances. The females 
suffer a high rate of mortality after being cut out of the egg- 
capsule, so that it is necessary to make a great number of ex- 
