xli 
occurred away from one another. He thought, however, that some of the cases of 
mimicry might be accounted for on other grounds than those supported by Messrs. 
Wallace and Bates, for if the Darwinian theory of a common descent were true, then 
the laws and principles of heredity could be applied to different species, as they have 
heretofore been to individuals. He proposed four classes, under each of which he 
believed some of these resemblances could be placed :— 
Ist. Resemblances purely accidental ; for the doctrine of chances would show that 
if there were in the world a sufficient number of species resembling one another, a 
greater or less number of these would be sure to occur in company. 
2nd. Resemblances the result of descent from a common parent; for it being 
understood that a certain character would be transmitted from parent to offspring 
through an indefinite number of generations, unless circumstances tending to alter it 
were brought to bear on that character, it could readily be perceived that some species 
of Lepidoptera might resemble one another in coloration, by reason of the resemblance 
of each to a common parent similarly coloured. 
3rd. Resemblances the result of exposure to similar circumstances; for undoubtedly, 
if the Darwinian theory were true, the coloration of species of Lepidoptera must be 
referred sooner or later to external causes operating on the organism. But the 
cases where mimicry occurred were cases in which the species, being constantly found 
together, were necessarily to a very great extent subjected to the same external 
conditions. Thus in a certain locality a species of Leptalis was found closely 
resembling a species of Heliconia, and in another locality a second and allied species 
of Heliconia was found. Mr. Wallace would say that this Heliconia differed from the 
first Heliconia because of the changed circumstances to which it was exposed: but 
with this second species of Heliconia was found a second species of Leptalis, differing 
from the first species of Leptalis in nearly the same manner as the second species of 
Heliconia differed from the first, and this was easily comprehensible, its companion- 
ship with the Heliconia having exposed it to exactly the same disturbing influences. - 
4th. This class was that to which Messrs. Bates and Wallace referred all these 
resemblances, and it was the only one that could correctly be spoken of as mimicry; 
the colour of the Heliconia, without any reference to common descent or to the 
operation of similar external agencies, being the determining cause of the colour of 
the Leptalis. 
Paper read. 
Messrs. Crotch and Sharp read a joint paper entitled ‘ Additions to the Catalogue 
of British Coleoptera, with Descriptions of New Species.” The additions were no less 
than seventy-one in number, the whole of which were exhibited; of these sixty had 
been described by continental authors, and eleven, belonging to the genera Ptilium, 
Atomaria, Telephorus, Sitones, Anthicus, Gyrophena, Philonthus, Lathrobium and 
Stenus, were characterized as new to Science. 
