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by predaceous creatures, a walking-leaf insect was shown, of a species 
which has given rise to some curious notions ; for, in 17!8, Bradley, a 
Fellow of the Royal Society, described and figured two kinds, of which 
he said that “the creature is hatched from eggs laid in the buds of the 
trees at the time the buds begin to shoot ; the insect is then nourished 
by the juices of the tree, and grows together with the leaves till all its 
body is perfected, and, at the fall of the leaf, drops from the tree with 
the leaves growing to its body like wings, and then walks about.” 
As examples of the second class, hairy, spiny, and bright-coloured 
-caterpillars were given, and also those which take the appearance of 
reptiles ; anda drawing was shown of the larva of the Pussmoth, which, 
when alarmed, withdraws its head within the first segment of the 
body, giving it the appearance of having a large flat face, with two 
black spots which look exactly like eyes, and regarding which the 
lecturer said ; “ Although to us there may not seem anything very 
terrible in the look of a caterpillar, we must remember that its com- 
paratively insignificant size has to be taken into consideration, and 
that in the eyes of a small bird it may present a very different aspect. 
And were it not for this question of size, we might think with one 
who, writing of another order of insects, the beetles, says— 
Their shape would make them, had they bulk and size, 
More hideous foes than fancy can devise ; 
With helmet-heads and dragon-scales adorned, 
The mighty myriads now securely scorned, 
Would mock the majesty of man’s high birth, 
Despise his bulwarks, and unpeople earth,” 
Among numerous other insects illustrative of the third class, 
“Col. Blathwayt drew attention to a two-winged British fly, volucella 
-bombylans, which consists of two varieties, extremely dissimilar in 
-appearance, and he believed that this curious dimorphism enabled 
‘them to be parasitic in the nests of two of our commonest species of 
shumble-bees, each variety closely mimicking a particular species of bee 
The remainder of the paper was devoted to the butterflies of one 
species which mimic those of another species, with a discussion of the 
various theories that have been advanced to account for it, and the 
lecturer, in conclusion, said ; One of the objections brought against the 
Darwinian theory of variation was that the variation would be so ~ 
