ARCTIA CAIAs ivi 
the block (with liquid Indian ink so as not to be liable to fade), 
and this should be pinned through with a very strong pin: for 
this purpose I myself prefer for No. 2 block, Kirby & Beard’s 
No. 2 pin, and for the larger blocks a No. 12 Continental pin 
37 mm. long. 
If the same sizes of cards be used for gummed specimens, it 
will be found that a series may be made up partly of gummed 
and partly of silver-wired specimens and yet retain a symmetrical 
appearance. 
Cambridge, Feb. 9, 1892. 
ABGTIAS \CALA- 
By J. ARrxKue. 
In the summer of 1890 I began a series of experiments in 
breeding Arctia caia, of which, although possessing little, if any, 
scientific value, it may be interesting to give a detailed account. 
My chief object was to obtain so-called ‘‘ varieties” by inter- 
breeding, and although much might be made of some of the 
forms I bred, still I am bound to confess they are, in my 
opinion, only slight departures from the usual type,—a small 
reward for all my trouble. 
Discouraging as this preliminary summing-up may be, still as 
my operations did not end until July, 1891, during the whole of 
which period the various phases of the insect were under constant 
and close observation, matters of extreme interest often arose. 
The eggs I found laid, in the wild state, upon the leaves of 
plants and trees,—once upon sallow, and once upon the leaf of a 
young lime tree. To the naked eye they appear pale, globular, 
and yellowish, and about the size of an ordinary pin’s head. 
They are laid in straight rows touching each other, and it is 
curious to observe how the parent moth will proceed for an inch 
ina straight line, and then turn off at an obtuse angle. The 
whole of the eggs form, as a rule, a closely laid batch. Under a 
strong magnifying glass, and viewed separately, the egg appears 
to be smooth, of a greenish colour, with a bronze-yellow lustre, 
changing first to chocolate and then to dark plum-colour before 
hatching. A powerful microscope shows a minute, apical zone, 
from which radiate lozenge-shaped “scales” pointed at each end, 
and resembling miniature Zulu shields. This radiation is 
regular, after which the ‘‘ scales”—minute, but very equal in 
size—are irregularly distributed over the whole of the shell as if 
marked out by a finely pointed needle. They reflect the most 
beautiful mother-of-pearl tints,—rose-pink, purple, green and 
blue. 
The caterpillar I pass over, and for two reasons. — First, 
it is so thoroughly well known as to need no description; 
