those common on beech leaves — much like the species shown in Fig. G. We 

 have also seen one or two wearing almost the same general scheme of pattern, 

 but done as to color wholly in brown, — and it happened that these were found 

 resting on twigs or stems, instead of leaf-edges. 



Class III. Purely mimetic leaf-edge larvae. Complete leaf-edge mimicry 

 without obliterative shading. The caterpillar shown in Figs. N, O, and P, 

 although strictly a leaf-edge larva, deviates so widely from one of the main 

 principles of that class as above defined that it must be treated separately. It 

 lacks, namely, all trace of obliterative shading, and its beautiful, shiny, oak- 

 leaf green, more closely like a leaf in surface-texture than is that of any of its 

 relatives we know, is of one uniform shade and tint, so that the larva can never 

 escape the full appearance of a solid, cylindrical body. But the perfect leaf- 

 color and texture of its green parts, in cooperation with the marvelously minute 

 counterfeit of the transparent, brownish worm-scars so common on oak leaves, 

 which the remainder of its body wears, make it — ^when, as is its wont, it hangs 

 inverted from a leaf — ^pass for the down-curled edge of it. The vein-pattern 

 is minutely copied on the larva's brown ^arts, and between the green 

 and the brown there is usually a narrow, irregular yellow line, exactly such as 

 the leaf commonly has. The broken-leaf-edge aspect is further aided by the 

 brown hump on the caterpillar's fourth segment. Altogether, though lacking 

 light-and-shade gradation, this is one of the most wonderful of protectively 

 colored caterpillars, and one of the very hardest to detect in situ. We have 

 sometimes found this caterpillar on beech, the leaves of which have worm- 

 scars very like those of oaks. 



Class III, Division A. (Fig. Q.) Structural and pattern mimicry of an 

 irregularly crumpled leaf-edge (thus approaching the scheme of the structur- 

 ally mimetic larva shown in Fig. S, though the latter is not a leaf-edge inhabi- 

 tant). This division includes un-counter-shaded leaf -edge caterpillars of a 

 different type from the oak larva — those, namely, which, by color, pattern, 

 and curiously humped backs, simulate the irregularly crumpled and withered 

 edge of a leaf. Their bodies are almost always crossed near the head by a 



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