272 HALF HOURS WITH INSECTS. TPackare. 



cially created to gain their livelihood by preying upon 

 them. 



One of the most striking cases of mimicry is afforded by 

 the caterpillar of the Toh/jje Velleda^ as avcU as that of its 

 ally, the lappet moth, which is found on apple trees, and 

 would easil}', when at rest, be mistaken for a swelling or can- 

 kered spot on the bark (Harris' Treatise on the Injurious 

 Insects of Mass., 1862, p. 379). Miss Dix, as quoted by 

 Harris on the same page, states that "when at rest the re- 

 semblance of its upper surface was so exact with the young 

 bark of the branch on which it was fixed, that its presence 

 might have escaped the most accurate investigation ; and 

 this deception was the more complete from the unusual 

 shape of the caterpillar, which might be likened to the ex- 

 ternal third of a cylinder. The sides of the body were 

 cloaked and fringed with hairs. It was of a pale sea-green 

 color above, marked with ash, blended into white ; and 

 beneath of a l)rilliant orange, spotted with vivid black. 

 When in motion its whole appearance Avas changed ; it ex- 

 tended to the length of two inches, and two-thirds of an 

 inch in breadth, its colors brightened, and a transverse open- 

 ing was disclosed on the back, two-thirds of an inch from 

 the head, of a most rich velvet-black color. It was sluggish 

 and motionless during the day, and active only at niglit." 



The gray color and roughened surface of many longicorn 

 and Buprestid beetles which rest in the daytime on the bark 

 of trees are undoubtedly protective, though why multitudes 

 of these two groups of insects are, on the other hand, 

 among tlie most highly colored and brilliant of any in exis- 

 tence, needs further investigation. Mr. Wallace observes 

 that these brilliant beetles would not be eaten by birds on 

 account of their very hard, dense tegument, but this will 

 equally apply to the gray and dull colored species, which are 

 evidently protected by these adaptive colors. The bright 

 colored species are the exception in the temperate regions, 



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