Metamorphosis of a Species of Cassida. 523 
Cuvier and Valenciennes, in which the lateral scales extend no 
farther than the ends of the rays of the pectoral fin, the whole 
length of the posterior portion of each side being smooth and 
soft, without scale or fold of skin. ‘The principal dorsal spe 
is smaller in this species than in either of the other two. The 
dorsal fin has ten rays, pectoral eleven, anal eight, caudal 
twelve. The general colours of all three species are green 
above, passing into silvery white below; but several of the 
specimens [ have preserved in spirits exhibit various shades 
of crimson and purple, as mentioned by your correspondent. 
Messrs. Cuvier and Valenciennes speak with less confi- 
dence of the specific distinction of the half-armed species (0) 
than of the other two (vol. iv. p. 493, 494.): but I am 
happy to be able, in confirmation of their views, to state, 
that, besides possessing examples of the three sorts from 
other localities, I succeeded, on different days during the 
month of August last, while fishing for whitebait in the 
Thames near Woolwich, in taking many, both young and 
adult, of all three species; but the first, as before stated, is 
by far the most common. 
I am, Sir, yours, &c. 
WILLIAM YARRELL. 
Ryder Street, St. James’s, Sept. 4. 1830. 
Art. VIII. On the Metamorphosis of a Species of Cassida. By T. H. 
Sir, 
I NEVER peruse your amusing Magazine without a con- 
sciousness of my indolence in not having contributed my mite 
to its entertaining pages. I cannot offer you subjects of much 
importance, but I shall be content, if what I may present to 
your notice should prove acceptable and be deemed worthy of 
room in your publication. 
The paper I have now to offer is in illustration of the 
metamorphosis of a species of Cassida; one, as curious as I 
have met with in the insect tribe. The drawing (fg. 128.) 
exhibits a species of Cassida, pretty common in the botanical 
garden near Calcutta; I found it abundantly spread over the 
foliage of a fine Convolvulus, almost to the destruction of every 
leaf. The larva is of an ovate form, depressed ; it is in length 
about half an inch, and one quarter of an inch broad, very 
soft and tender, and so delicate in texture, that the intestines 
and circulation are evident with the aid of a lens, It has 
six short flattened legs, which are hid in the pinnated sete 
MM 2 
