370 
J. BRONTE GAT UN BY. 
embryo or is swallowed by the latter. The live nuclei, to 
which the temporary persistence of the extruded mass is due, 
may develop the microsome granule ( GEC .) drawn in PL 11, 
fig. 21 a. This is the case with the nuclei marked LEN. in 
Pi. 12, fig. 82. (See addendum, p. 30.) 
The Nervous System. 
The nervous system can be recognised very early ; it arises 
from the multiplication of ectodermal cells in the usual 
manner found in insect larvae, but it never becomes properly 
separated off from the ectoderm. Even in late larval life the 
nervous system seems l< coarsely” made; that is to say, it is 
formed of comparatively few cell elements which are not 
differentiated in the characteristic manner, and there are no 
such things as nerves in the sense of offshoots or twigs to 
organs, such as exist in other larvae, such as Yespa. The 
nerve-cells do not differ in any way from other cells in the body, 
always excepting germ-cells. In PI. 11, fig. 18, the nerve- 
chord is seen in a rudimentary condition, and consists of the 
bottom row of nuclei marked N. C. N., and an unknown 
number of the row above. In PL 11, fig. 21, the brain (BE.) 
and nerve-chord ( N.C .) are cut longitudinally. In PL 11, 
fig. 22, PL 12, figs. 33 and 38, a better view of the chord in 
transverse section is seen, and in PL , fig. 29, the brain (BE.) 
is cut transversely, to illustrate its close connection with the 
epidermis (E/P.) and oesophagus (S TD.). No such things as 
ganglia exist, and the chain ends a little before the germ- 
pocket; it does not reach the proctodaeum. In late stages 
(PL 12, fig. 88, N. C.) it becomes an increasingly difficult 
matter to recognise the chain, so stretched does it become, 
and by the time the larva has swallowed all the yolk in the 
Donacia egg, the nervous chain is for most of the hinder 
part of its length quite unrecognisable. The oesophageal 
connectives seem to consist of single cells applied to one 
another (PL 12, fig. 30, CES. CON.), and are extremely 
rough. 
