50 ON PLANTS AND INSECTS. [LECT. 



family of moths (the Geometridce) the prevailing colour is 

 brown. These caterpillars, however, escape observation 

 by their great similarity to brown twigs, a resemblance 

 which is heightened by their peculiar attitudes, and in 

 many cases by the existence of warts or protuberances, 

 which look like buds. Some, however, even of these 

 caterpillars, when very young, are green. Again, some 

 caterpillars are white. These either feed on and burrow 

 in wood such are, for instance, the species of Sphecia, 

 Trochilium, and Zeuzera or on roots, as the ghost- 

 moth (Hepialus humuli}. Hipparchia hyperanthus 

 (the ringlet butterfly) also has whitish caterpillars, and 

 this may at first sight appear to contradict the rule, 

 since it feeds on grass. Its habit is, however, to keep 

 at the roots by day, and feed only at night. 



In various genera we find black caterpillars, which 

 are of course very conspicuous, and, so far as I know, 

 not distasteful to birds. In such cases, however, it will 

 be found that they are covered with hairs or spines, 

 which protect them from most birds. In these species, 

 the bold dark colour may be an advantage, by rendering 

 the hair more conspicuous. As instances of caterpillars 

 which are black and hairy, I may quote, among our 

 English butterflies, Melitcea einxia, M. artemis, M. 

 athalia, M. selene, M. dia, M. euphrasy ne, Argynnis 

 aglaia, Vanessa polychloros, V. io, and V. antiope ; 

 while among moths, there are Arctia villica, A. caja, 

 and Heraclea dominula. I do not know any large 

 caterpillar which is black and smooth. 



Brown caterpillars, also, are frequently protected by 

 hairs or spines in the same way. As instances may be 

 mentioned Cynthia cardui, Argynnis lathonia, Erio- 



