222 NATURAL HISTORY OF WASPS. 
meant for real work, and are not merely the rudi- 
ments of something which is to be developed into 
a useful organ in the perfect insect. When they 
have served their turn they are cast off, with the 
first skin, and may be recognized lying at the 
bottom of the cell, or hanging on its walls with the 
discarded egg-shell. 
But we have not discarded the egg-shell yet. For 
the larva, after its first moulting, still, for a while, 
remains anchored by the tail to the place of its 
birth, fixed in its egg-shell. Though the tether 
becomes hourly longer, and the larva has more ex- 
tended movement in every direction. As the larva 
grows it has to seek, further back in the cell, a 
position adapted to its future requirements. This 
change of position would seem to be a very perilous 
operation, judging from the large number of small 
larve which are cast out of the nest. For, if the 
embryo loses its hold it falls out of the cell, and the 
workers, acting on the maxim that everything out of 
its place is dirt, immediately remove the helpless 
grub from the nest. They do not kill or eat the 
grubs, at least, not in the first instance, they merely 
carry them away, as they would any other useless 
material. Hunter* has seen the wasps replace im 
empty cells grubs which had fallen out of the nest. 
But this is not their usual practice. Something of the 
same kind has been observed on a larger scale, where 
larvee of one nest were transferred to another at 
some yards distance.t But it is doubtful whether 
* «Posthumous Works,’ Vol. I, p. 85. 
+ Smith’s ‘Catalogue of British Aculeate Hymenoptera,’ 1858, 
p. 214. 
