Mr. A. G. Butler on new Species of Diurnal Lepidoptera, 285 
the float must be entirely subject to the will of the animal, 
to its appreciation, if I may so speak; and this is really the 
case, as it never makes use of the mucosity of its foot except 
when it feels its float to be insufficient, just as the spider 
employs the silk with which its spinnerets furnish it only when 
injuries have rendered its web unfit to capture the prey which is 
necessary for its existence. 
It is unnecessary to say that a gaseous secretion is inadmis- 
sible, and that there is nothing to warrant its existence. 
From all that precedes, I may justly be asked whether I have 
seen in my aquaria Janthine entirely deprived of their floats re- 
construct new ones. I reply that the animals did not live long 
enough for this; it is with them as with the spider to which 
I have just referred: if we destroy its web, it reconstructs this, 
but at the expense of its body; and if we continue without 
allowing it to capture a prey, if its organization does not pro- 
vide itself with what is necessary to repair the losses caused by 
secreting silk, it is seen to die of inanition. In the same way 
here: the Janthine are animals of the high sea; they find in 
these regions their proper food, which they did not meet with, 
in all probability, in my aquaria; hence they only lived a short 
time, exhausted by their exertions and by the want of nourish- 
ment. 
In conclusion, I will remark that Cuvier’s opinion, so full of 
reserve and doubt, cannot be maintained. The float of the 
Tanthina cannot in any way represent an operculum, or even its 
distant analogue. 
XXXI.— Descriptions of some new Species of Diurnal Lepidoptera 
in the Collection of the British Museum. By Anrruur G. 
Burier, F.Z.8., Assistant, Zoological Department, British 
Museum. 
Limenitis Calidasa, n. sp. 
L. Calidasa, Moore, MS. 
Ale supra fuscze, fascia media irregulari albo-viridescente, anticarum 
maculas octo ineequales formante, posticarum integra, in medio 
latiore ; area basali fascia media interrupta rubra nigro circum- 
data, basi fascia simili obscura; area apicali fascia submarginali 
rubra, maculis nigris utrinque marginata ; margine postico pallido, 
lunulis nigris marginato. 
Corpus fuscum ; antenne nigra, rubro acuminate. 
Ale antice subtus area basali viridi, fascia media rubra a vena media 
partita, lineaque basali obliqua nigra; area apicali cinerea, venis 
apud costam rubris, linea rubra undata, maculisque nigris sub- 
marginata; fascia media velut supra nigroque utrinque marginata; 
