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patch on the orange-tip butterflies (which, Mr. Darwin denies, are 
protective), may serve the same purpose. It is, in fact, somewhat 
remarkable how very generally the black spots, ocelli, or bright 
patches of colour are on the tips, margins, or discs of tlie wings ; 
and as the insects are necessarily visible while flying, and this is 
the time when they are most subject to attacks by insectivorous 
birds, the position of the more conspicuous parts at some distance 
from the body may be a real protection to them.”—(Wallace. 
Tropical Nature, p. 202.) 
“Other species of aphides (Eriosoma), and many of the coccidm, 
secrete a white, flocculent, waxy cotton, under which they lie 
concealed. In many of the Homoptera, this secretion only amounts 
to a white powder, covering the body, as in some of the Fulgoridse. 
In others it is more abundant, and it reaches its extreme limit in 
a species of Phenax that I found at Santo Domingo. The insect 
is about an inch in length, but the waxy secretion forms a long 
thick tail of cotton-like fibres, two inches in length, that gives the 
insect a most curious appearance when flying. This flocculent mass 
is so loosely connected with the body that it is difficult to catch 
the insect without breaking the greater part of it off. Mr. Bates 
has suggested that the large brittle wings of the metallic Morphos 
may often save them from being caught by birds, who are likely 
to seize some portion of the wide expanse of wing, and this break 
ing off, frees the butterfly. Probably the long cumbersome tail of 
the Phenax has a similar use. When flying, it is the only portion 
of the insect seen ; and birds trying to capture it on the wing are 
likely to get only a mouthful of the flocculent wax.”—(Belt. 
Nicaragua, pp. 22 g-230.) 
Even when the insect has been captured by the enemy, 
and subsequently rejected, this will not be so dangerous as 
it otherwise might be, owing to the elasticity of the 
entire structure of some insects. 
“ Most of the species of Danais and Acrma . . . possess (a) 
means of defence, which, as far as I am aware, has not hitherto 
been recorded, viz., the remarkable elasticity of their entire structure. 
No pressure of the thorax, short of absolute crushing of the tissues, 
suffices to kill or even paralyse these butterflies ; and the collector 
who treats them as he would species of other families, soon finds 
his collecting-box alive with its struggling occupants. So flexible 
are the wings, that the insect generally succeeds in withdrawing 
them from crossed fences of pins which form a complete barrier to 
any motion on the part of ordinary butterflies ; and, however bent