v4) 
them. Examples were here shown of the Comma Butterfly, the 
Orange-tip at rest on cow parsley, the Buff-tip Moth resembling 
a broken twig, and the Red Underwing Moth. 
_ Melanism, Mr. Hopson stated, is now being investigated by 
a Committee of the Royal Society. Insects which normally are 
of a light colouration are becoming darker, in some cases almost 
black in and around our large towns. A series of the Peppered 
Moth (A. betularia) varying from a very light colour to almost 
black, was shown from the Hampstead district, illustrating this 
change in colouration. 
In tropical and sub-tropical countries the Danaine, Helico- 
niine, Ithominze and Acraemine are known to be practically free 
from the attacks of animals, which devour other Lepidoptera 
quite readily. These insects are gaudily coloured, but Bates, 
when examining captured specimens, found that many did not 
really belong to these families, although, at first sight, they re- 
sembled them. He then promulgated what is known as the 
Batesian theory. Certain species, such as Papilios, Pierids, Nym- 
phalines, which are preyed upon by insectivorous animals, he 
said, have, by natural selection, come to resemble distasteful 
‘species, such as Acroea and the Heliconiine, and so secured a 
certain amount of protection by thus masquerading in the dress 
of a “ protected species.’ 
The following exhibits were shown :—The so-called auditory 
organs in the opossum Shrimp (Mysis) by Dr. J. W. Williams, 
F.L.S.; a series of Trilobites by Mrs. Park and Mr. P. Macleod 
Yearsley, F.R.C.S.; the skin of a Hornbill (Buceros cavatus) by 
Mr. Hugh Findon ; and protoplasmic streaming in the Canadian 
water-weed (Elodea canadensis) by Mr. K. I. Marks, F.R.M.S. 
Friday, November 11th, 1904. Sir Samuel Wilks, Bart., 
- F.R.S., in the chair. 
Mr. C. Nicholson, F. E. S., read a paper (illustrated with 
specimens and artificial bogs) on ‘* Bog Plants.’’ He first dealt 
with the nature, composition, birth, life and death of bogs, explaining 
iy oy 
that it was peat bogs about which he proposed to speak. He | 
then proceeded to show that the conditions under which the bog- 
flora existed were peculiar in that the amount of soluble material 
in the bog-water prevented free absorption by the roots. Hence 
the plants resorted to various devices to check transpiration, such 
as development of hairs, narrowing of leaves, thickening of cuticle, 
etc. Moreover, the saturated soil (peat) was badly aerated, and 
therefore oxidization was slow, bacteria were scarce, and nitrogen 
_ difficult to obtain ; hence some species had developed insectivorous 
habits, providing ‘the lacking nitrogen by catching and digesting 
