( 22) 
ground, was a predominant feature of the whole series, and, 
though especially characteristic of MWylothris, appeared in some 
instances to exist independently of that genus. Another 
prevalent aposeme was the orange or scarlet basal flush well 
seen in Mylothris riippellii. It was significant that both these 
warning marks tended to be better developed on the under- 
surface, 
Dr. Drxery concluded by drawing attention to the fact that 
these colour-assemblages were by no means isolated clusters. 
On the contrary, they passed into one another in many direc- 
tions, though this was not easily observed in an exhibit 
arranged like the present. As a matter of fact, the whole 
array of specimens shown might be regarded as forming a net- 
work, each individual being connected with all the rest by a 
larger or smaller number of gradations. It would be seen on 
tracing out these lines of connection that they ran to a very 
large extent independently of aftinity. The phenomena were 
indeed in many respects comparable with the facts regarding 
mimicry in the Neotropical region, to which he had drawn 
attention in ‘‘ Nature” for October 31, 1907, pp. 677-8. 
[Ixxv 
ASSOCIATION OF ALLIED Forms or SourH AMERICAN BurTTEr- 
FLies.—Dr. G. B. Lonestarr exhibited a case containing 3) 
Ithomiine butterflies of 11 species, belonging to 6 genera, 
all taken in a little over an hour, on March 20th, 1907, at 
about 4.0 p.m. near Caracas, Venezuela, some 3600 feet above 
sea-level. They were disturbed in a shaded gorge and all 
taken on a piece of moist ground measuring perhaps 60 yards 
by 10 yards. They were all flying together like a cloud of 
gnats and many more might have been secured, but the 
number of distinct species was not recognized at the time. 
This habit of butterflies of this group thus congregating 
together was described by Bates.* It affords a striking 
exception to Darwin’s principle that closely allied forms are 
[Ixxvi 
not usually found together. When on the wing out of the 
sun the clear-winged species were difficult to see, only the 
white or yellow markings catching the eye, but in the 
* Trans. Linn. Soc. 1862, pp. 539, 541. 
