34 CONTROLLED NATURAL SELECTION 
without doubt, that the upper surfaces are 
conspicuous in Nature and the under ones 
inconspicuous. 
It is probably an advantage for Admiral 
butterflies to be able to see other Admiral 
butterflies on flowers, from a distance; and 
thus to find good food and mates, &c. 
The Tadpole (Rana Temporaria), when 
very young, is coloured uniformly black. At 
this stage, they keep together in colonies, 
forming black wriggling masses, as noticeable 
from under water as from above, and make, 
when disturbed, no effort at concealment. 
It is noteworthy that the black of the young 
tadpole, like the black of the frog’s ovum, 
may be for the purpose of absorbing the sun’s 
heat. 
Experiments have shown that young tad- 
poles are unpalatable to both birds and fish ; 
it seems, therefore, that they can with safety 
render themselves conspicuous, and utilise 
the beneficial heat-absorbing property of 
blackness. 
Sufficient examples, and they could be 
multiplied almost indefinitely, have now been 
given, to show that many animals are con- 
spicuous in Nature and make no attempt to 
conceal themselves. 
