MEANS OF DEFENCE OF INSECTS. 



179 



Many insects, also, are like pebbles and stones, both rough 

 and polished, and of various colours ; but since this resem- 

 blance sometimes results from their attitudes, I shall enlarge 

 upon it under my second head : whether, however, it be 

 merely passive, or combined with action, we may safely re- 

 gard it as given to enable them to elude the vigilance of their 

 enemies. 



A numerous host of our little animals escape from birds 

 and other assailants by imitating the colour of the plants, or 

 parts of them, which they inhabit ; or the twigs of shrubs or 

 trees, their foliage, flowers, and fruit. Many of the mottled 

 moths, which take their station of diurnal repose on the north 

 side of the trunks of trees, are with difficulty distinguished 

 from the gray and green lichens that cover them. Of this 

 kind are Miselia aprilina and Acronycta Psi. The caterpillar 

 of Bryophila Algce, when it feeds on the yellow Lichen juni- 

 perinus, is always yellow ; but when upon the gray Lichen 

 saxatilis its hue becomes gray. 1 This change is probably 

 produced by the colour of its food. Leptocerus atratus, a 

 kind of May-fly, frequents the black flower-spikes of the 

 common sedge ( Carex riparia), which fringes the banks of our 

 rivers. I have often been unable to distinguish it from them, 

 and the birds probably often make the same mistake and pass 

 it by. A jumping bug, very similar to one figured by 

 Schellenberg 2 , also much resembles the lichens of the oak on 

 which I took it. 



The spectre tribe (^Phasmd) go still further in this mimi- 

 cry, representing a small branch with its spray, I have one 

 from Brazil eight inches long, that, unless it was seen to 

 move, could scarcely be conceived to be any thing else ; the 

 legs, as well as the head, having their little snags and knobs, 

 so that no imitation can be more accurate. Perhaps this 

 may be the species mentioned by Molina 3 , which the natives 

 of Chili call " The Devil's Horse." 4 



Other insects, of various tribes, represent the leaves of 



1 Fabr. Vorlesungen, 321. 2 Cimic. Helvet. t. iii. f. 3. 



3 Hist, of Chili, i. 172. 



4 Since the first edition of this volume was printed, a lady from the West 

 Indies looking at my cabinet, upon being shown this insect, exclaimed " Oh, 

 that is The Devil's Horse ! " 



N 2 



