1881] 
251 
the leaf, it did not go on from the very end of the cut already made, 
but began again at a point a little distance further back, thus finally 
bringing out the channel with a shorter rounder curve, which had the 
effect of making the detached piece of leaf more symmetrical in 
outline. It w r as now afloat, with its ventral and anal legs clinging to 
its raft, but very soon it applied its thoracic legs to the fixed part of 
the leaf, and, guiding its course by them, conveyed itself and its raft 
under the leaf, apparently looking for a suitable place, whence to cut 
the other half of its case ; presently it seemed to find what was 
wanted, the floating piece was made fast, and after some hours the 
upper half was cut out and detached, and the larva floated in its finished 
dwelling. Continuing to watch it, the next thing I noticed was a rapid 
horizontal motion of the head and front part of the body of the larva, 
just within the case from one side to the other; then turning about, 
after a pause, the larva repeated this movement at the other end, rested 
awhile, and again repeated the movement : next it turned round again 
and protruded its head from the former end of the case, with the air 
of taking a survey of the outside, and whilst it was in this position a 
small silvery air-bubble floated out from inside the case, and when the 
larva, turning round once more, put out its head from the other end 
as rf surveying that also, the bubble seemed somehow to be attracted 
and moved over and settled close to its head : after this, the larva set 
about feeding, and journeying for about an inch, reached the stem of 
the plant and fed on it for some time, and then moored its case to the 
stem by a thread and rested : afterwards I saw it eating patches of 
leaf-cuticle, soon effecting a large hole through the entire substance ; 
next day I saw it again eating, and noticed that from time to time it 
stopped this occupation, withdrew its head into its case, and made from 
five to thirteen of these rapid movements from side to side; vigorous and 
rapid as these movements were, they did not shake the case, and I think 
were quite independent of it ; indeed, I am disposed to regard them 
as in someway connected with the act of respiration, being analogous 
to the movements of the larva of Parciponyx stratiotahs , described by 
me at p. 161 , vol. xii, of this Magazine. Bearing on this point also 
will come some observations I made on the presence of water within 
the case ; once or twice it happened that a larva had brought its case 
into such a position that a good portion of it was above the surface of 
the w r ater, and I was able to look down the opening at the end into 
the interior, quite through to the other end, and I made sure that it 
was full of water, and once I could notice a small silvery air-bubble 
clinging to the side of the case: probably, when the larva fastens up 
