1868.] On the Colowr-patterns of Butterflies, 323 
when it amounted to 15,000,0002. sterling, since which period the 
production of California has steadily declined, and the present annual 
return of the precious metal does not much exceed 5,300,000U. 
The total value of the gold produced in the state, from the 
time of the discovery of that metal in 1848 to the close of 1866, is 
estimated at 167,260,0002. 
Ill. ON THE COLOUR-PATTERNS OF BUTTERFLIES. 
By Rev. H. H. Hicerns, M.A. 
Tue petals of flowers, the plumage of birds, the surfaces of shells, 
the hides of quadrupeds, the integuments of polyps, and the wings 
of insects, are some of the chief objects distinguished by a great 
variety of natural colour-patterns. 
All that I propose to attempt in the present instance is to offer 
a few remarks on the proximate origin and general configuration 
of the patches, bands, and spots of colour which adorn the wings of 
the Rhopalocera. . 
By the use of the term “proximate origin,” the inquiry is 
limited to the appliances immediately engaged in producing the 
results under consideration ; an inquiry which cannot conveniently 
be separated from the question, whether amidst the apparently 
capricious and endless varieties of colour-patterns on the wings of 
butterflies, may be recognized the elements of a prevailing arrange- 
ment. 
An example of the kind of agency contemplated may be found 
in the serrated edge of the leaf of a Potentilla, which, if is said, is 
the result of a certain configuration of organs discernible in the 
leaf-bud ; or, again, the spines on the shell of a Murex, which may 
be shown to be the result of tentacular appendages periodically 
developed in the mollusc. 
The physical conditions which have preceded so delicate a result 
as the shading of the colours on the wing of a butterfly, require a 
kind of investigation which must be attended with corresponding 
difficulties. But it will be admitted that in no case is a spot or a 
band added or obliterated except through the instrumentality of 
antecedents sufficient to produce the result in question. How far 
these antecedents are capable of being investigated has yet to be 
determined. 
The rudiments of wings, according to Burmeister, may be ob- 
served when the caterpillar has completed its third moulting and 
has attained its full size. “They at first present themselves as 
short viscous leaves, the substance of which greatly resembles that 
