604 Color and Pattern and their Uses 



green (variable resemblance, depending on their nurture) and roughened 

 and tubercled like a bud-scarred bit of twig. The absence of the middle 

 prop-legs prevents the harm to this illusion that would come from their pres- 

 ence. An interesting point in this simulation and one which is commoner 

 in such cases than has been generally referred to is the combining of a 

 habit or kind of behavior with the structural and color modification to make 

 the illusion successful. 



Another familiar and extreme case of special protective resemblance is 

 that of the walking-stick, or twig-insect, Diapheromera jemorata (Fig. 790), 

 a Phasmid wide-spread over the whole of our country. The absence of 

 wings, the extreme elongation and slenderness of body and legs, and the 

 dichromatic condition, individuals being either green or brown, all com- 

 bine to make this insect a masterpiece of deceit. The moths of the genus 

 Cymatophora and their larva? also mostly harmonize excellently with the 

 gray bark on which they rest; the moths adding to their general simulation 

 the curious habit of resting often with folded wings at an angle of 45 with 

 the tree-trunk, head downwards, with the curiously blunt and uneven wing- 

 tips projecting, so as to imitate with great fidelity a short broken-off branch 

 or chip of bark. Numerous other moths and caterpillars resemble bark 

 and habitually rest on it. The Catocalas, Schizura, and others are ex- 

 amples familiar to the moth-collector. 



Any field student of insects by paying attention to the matter of special 

 protective resemblance can soon make up a formidable list of examples. 

 Some of these may appeal more to him than to persons seeing his speci- 

 mens in the collecting-boxes, and some indeed will probably be questionable 

 to other naturalists. But nevertheless no collector or field student but has 

 noted many examples of this clever artifice of Nature to protect her 

 children. 



Warning colors. If the field student may be relied on to note and record 

 a long list of insects colored and marked so as to harmonize well with their 

 general environment or with some specific part of it, he may also be relied 

 on to bring in a list of opposites : a record of bizarre and conspicuous forms, 

 colored with brilliant blues and greens and streaked and spotted in a man- 

 ner utterly at variance and in contrast with the foliage or soil or bark or 

 whatever is the usual environment of the insect. The great red-brown mon- 

 arch butterfly and its black-striped green and yellowish larva, the tiger- 

 banded swallowtails, the black and yellow wasps and bees, the ladybird- 

 beetles with their sharply contrasting colors, the brilliant green blister-beetles, 

 the striped and spotted Chrysomelids in all these and many others there 

 can be no talk of protective resemblance: if only such a paradoxical theory 

 as protective conspicuousness could be established, then these colors and 

 markings might well be explained by it. 



