2i4 ROMANCE OF THE INSECT WORLD CHAP. 



are reproduced with marvellous fidelity. The 

 Geometrae are a widespread and numerous tribe, 

 divided into an immense number of species there 

 are between two and three hundred in this country 

 alone, a result that has been brought about, doubtless, 

 by their acquisition of a form and attitude so well 

 suited for purposes of concealment, admitting of their 

 success in life's race, to the detriment of larvae 

 with less perfected methods. In their wanderings 

 Geometrae have come to feed upon a variety of food 

 plants. These changes have in some cases necessitated 

 corresponding modifications of attitude, of colour, or 

 of form, in order to bring the larvae into harmony 

 with their environments. 



Caterpillars of other groups secure protection by the 

 imitation of surrounding vegetative objects, though 

 perhaps hardly to such an astonishing degree. Some 

 resemble the bark of thick branches, and repose against 

 the bark, closely adhering to it. The furrow that 

 they would make with the branch is obliterated by 

 hairs, or by a row of fleshy projections, at least in all 

 probability this is the use of these structures. The 

 appearance of lichens* is also commonly simulated by 

 larvae that ordinarily rest on lichen-covered bark. 

 " Stick caterpillars " in the earlier portion of their 

 career do not stand upon the branches, but upon the 

 leaves of the plant on which they feed, where the 

 twig-like attitude would be inappropriate. Some are 

 green in colour, so that they correspond with the 

 leaves ; in other cases the caterpillars are brown, as at 

 later times, and the attitude is then often modified to 

 avoid danger. Twisting itself into spiral or zigzag 



