220 MEANS OF DEFENCE OF INSECTS. 



we may safely regard 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 tv^'igs 

 of shrubs and trees ; their foliage, flowers, and fruit. 

 Many of the mottled moths, Avhich take their station 

 of diurnal re]>ose on the north side of the trunks of 

 trees, are with difliculty distinguished from the gray 

 and green lichens that cover them. Of this kind are 

 Noctua aprUina and Psi^ F. The caterpillar of N. Al- 

 gce^ F. when it feeds on the yellow JJchcn juniperinuSy 

 is always yellow ; but when upon the gray Lichen saxu' 

 tills its hue becomes gray''. This change is probably 

 produced by the colour of its food. Pltri/ganca otra, 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 unalile to distinguish 

 it from them, and the birds probably often make the 

 same mistake and pass it by. — A jumping bug, very si- 

 milar to one figured by Schellenberg'', also much re- 

 sembles the lichens of the oak on which I took it. 



The Spectre tribe (Phasma, Licht.) go still further 

 in this mimicry, 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 imita- 

 tion can be more accurate. Perhaps this may be the 

 species mentioned by Molina', which the natives of 

 Chili call the " The Devil's Horse." 



^ Fabr. Vorlcsuiisen,S2l. " Cimic. Ilelvet. t. iii./.3. "Hist. pfC/iiIt,[. 1T2. 



