MATURATION OF UNFERTILISED EGG IN TENTHREDINIDA. 567 
I seen any trace of a centrosome; the chromosome number 
appears to be eight (Pl. 36, figs. 24, 25) (see below). The 
spindles of the second maturation division lie in the same 
line as the first, and when the chromosomes have reached the 
ends, each group gives rise to a large reticular nucleus with 
well-developed nuclear membrane. In this way arise four 
similar nuclei, lying in a line nearly perpendicular to the 
edge of the egg, the outer one being close to the edge, the 
two middle ones near together in the middle of the little mass 
of protoplasm, and the inner one on the inner edge of the 
protoplasm, almost embedded in yolk-granules (figs. 4, 5, 6). 
Of the four nuclei, the two outer are the two halves of the 
first polar nucleus, the third is the nucleus of the second 
polar body, and the innermost is the female pronucleus, 
which in the parthenogenetic egg will give rise to the 
embryo. After the nuclei have been formed the remains of 
the spindles are still seen between them, and at a rather later 
stage one or two round, rather faintly stained bodies are 
found near the nuclei (fig. 8); these bodies are probably 
erived from the spindles, and correspond to what Henking 
called the ‘ thelyid.” 
At first all four nuclei agin ilar in size and shape, and lie 
nearly at even distances from one another, but very rapidly 
changes begin to take place. ‘The outermost gets pressed 
against the wall of the egg, becomes flattened in shape, and 
in a short time becomes unrecognisable, and disappears. 
Meanwhile the innermost (the female pronucleus) begins to 
move deeper into the egg, and at the same time travels 
towards the anterior end, and in so doing becomes so closely 
embedded among the deeply staining yolk-granules that after 
a very short time it is very hard to find. While these pro- 
cesses are in progress, the two middle nuclei, viz. the second 
polar nucleus and the inner half of the first polar nucleus, 
move towards one another, and soon come so closely into 
contact that each becomes nearly hemispherical, the flat sides 
being pressed against each other. The chromatin of these 
two nuclei, which has hitherto been distributed in a fine 
