group of Butterflies, Potaro District, British Guiana. 417 
a collection of these brown and black insects is found on 
the Hupatorium flowers, it is not so invariably. On May 
14th, 1901, I remember being disappointed (from the 
collector’s point of view), in coming upon a bush where 
there were only Mechanitis polymnia and Ceratinia euclea 
(C. philidas and C. bendis) present. Such a case as this 
clearly shows the value it is to these members to have 
been brought into harmony with the colours of the 
dominant Melinza mneme. As although these species are 
only commencing to conform to the main colouring of the 
model they are able even among themselves to alight on 
these flowers and be comparatively immune from danger. 
It would have been interesting had every specimen of 
Melinea mneme been retained to see the accurate propor- 
tions of the different forms. I have actually kept 70 set 
specimens, and these are divided up as follows :— 
Melinxa mneme. 
Hind-wing distinctly banded 40 = 57 % Upper-side and 
Hind-wing obscurely banded 22 = 3147 Wadenads 
Hind-wing with band obliterated 8 = 114% 
Thus only 1 in 9 is heavily black, and this I have more 
than once verified to be the approximate percentage. 
A further interesting phase of variation is the presence 
or absence of the red marks just before the yellow apical 
band on fore-wing. The specimens give these figures :— 
UPPER-SIDE. UNDER-SIDE. 
Fore-wing with large red spots or band 
before yellow apical bandits.) 34)": 12) S50 hy, 
Fore-wing with faint or oreatly suffused 
spots . 40 5 Or — 297, 
Fore-wing withred spots, band obliterated, 
or nearly BO Pet) een es HLS — O65 / —- 
These comparative figures are of great interest, as 
although this species is so dominant in point of numbers, 
the influence it exerts with its dark forms is very small 
indeed compared with that of its banded forms. It there- 
fore becomes tolerably clear that the allied Melinxa,— 
crameri—which, although not nearly such a common 
species, but has a very constant black pattern, must 
have acted very strongly to create the powerful darkening 
tendency in the hind-wing. 
