MIMIC BY. 539 



Its larva feeds on sallow and willow. Petasia cassinea is said in 

 the daytime " to sit upon old posts and railings, and is very hard 

 to see, from its close resemblance to a bit of decayed wood, or to 

 the greyish-brown lichens. Its extended and tufted feet, and 

 rough scales at the edge of the fore wings, all help to complete 

 the deception."* Cymatophora duplaris exhibits a purpose in 

 active mimicry of the highest description, both as a caterpillar 

 and a perfect moth. The larva during the day "conceals itself 

 in a habitation formed of green leaves united by silken threads 

 upon the tree. At night it comes forth to feed/'f The moth 

 sits in the daytime on the branches of trees. " When shaken 

 out it falls straight to the ground, and lies among the dead 

 leaves. "+ Arsilonche venosa, in colour and markings, like those of 

 so many other fen-frequenting species, is accurately suited to its 

 habit of hiding in the daytime among the dead leaves of reed, 

 sedge, and marsh-grasses. § Agrotis ashworthii " sits in the 

 daytime on limestone rocks, or hides among loose stones. In 

 appearance it closely resembles the blue limestone, and it has 

 the sagacity to hide itself in chinks and crevices, where this 

 resemblance greatly assists in its concealment." || All these 

 examples scaraely bear out an automatic or semi-automatic 

 action ; we seem to see among these lowly organised insects — 

 referring, of course, to sense organs — a capacity and endeavour 

 to use their environmental resemblances to the best advantage. 

 There may be much heredity in such an aptitude, but the intelli- 

 gent concealment would not be questioned if practised by the 

 higher animals. 



The instances of active mimicry just given almost appertain 

 to decorative art, and in fact represent the impostor who with 

 borrowed plumes flaunts in the open. We now resume the 

 series of more modest simulation, in which advantage is taken of 

 similarly coloured objects by which concealment may be effected. 

 These may nearly be said to reflect the methods of the impostors 

 who attach themselves to majorities, winning causes, and crowds, 

 where they are submerged in resemblances, and, undetected, reap 

 the corresponding advantage. The Australian genus of Sea- 



:;: ' The Lepidoptera of the British Inlands,' vol. iii. p. 157. 

 f Ibid. p. 195. t Ibid. p. 196. § Ibid. p. 277. 



|| Ibid. p. 383, 



