DEVELOPMENT OK TRICHOGRAMMA EVANESCENS. 173 
larva the germ cells lie in a pocket beneath the proctodeum, 
that is, on the ventral edge of the body-cavity. In the 
earliest stages the germ cells may be seen moving in this 
direction (fig. 14 of PL 11, in the direction of the arrow). 
One germ cell (M.) has begun its migration. By the stage in 
PL 11, fig. 15, the germ cells have sunk right into the ventral 
edge of the posterior pole, pushing aside the blastoderm 
nuclei. In Pl. 11, fig* 22, which is a somewhat oblique longi- 
tudinal section, this inpushing is finished, and the germ 
pocket is formed by the nuclei ( X ., X.X.). The latter are 
quite early set aside for this work, and continue in that 
position in late larval life. During the time the other organs 
are being differentiated the germ cells remain closely embraced 
by these cells ; and just when the lumen of the gut is appearing 
(Pl. 11, figs. 27 aud 28) the germ pocket has the appearance 
drawn in PL 12, fig. 37, in transverse section, and in PL 12, 
fig. 34, in longitudinal. The germ cell socket is enclosed by 
about four cells, and contains the germ nuclei in what appears 
to be a syncytium, though faint cell outlines and slight 
vacuolisations can sometimes be noticed. The germinal 
cytoplasm stains very faintly in plasma dyes. In PL 12, 
fig. 34a, I have drawn an enlarged view of the pocket in 
order to show the staining reactions. In the case of nearly 
every nucleus the nucleolus alone can be made to stain. 
Regarding the number of nuclei in the pocket I could count 
seven in one, and in another six, but there were always 
doubtful nuclei at or on the edge of the syncytum, which 
may or may not have been germ nuclei ; it is probable that 
the number of germ cells is subject to variation, though I 
have never found less than six. 
After the stage drawn in PL 12, fig. 34, my material is not 
very good, but at a stage a little after the time the larva has 
distended itself with the yolk of the host, the germ cells 
seem to become almost similar to the somatic cells, and 
•amitotic division begins. The exact details and further 
confirmation of the facts cannot be given at present. 
It will be noticed in PL 11, figs. 21, 22, and Pl. 12, figs.‘34 
