HYDROCAMPA NYMPH^IATA. 97 



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 move- 

 ment at the other end, rested awhile, and again re- 

 peated 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 if 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 some way connected with the act 

 of respiration, being analogous to the movements of 

 the larva of Parayonycc stratiotata, described by me 

 at p. 161, Vol. XII, of the E.M.M. [and repeated at 

 p. 82 of this volume]. 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 

 water, and I was able to look down the opening at 

 the end into the interior, quite through to the other 

 VOL. ix. 7 



