PROTECTIVE AND AGGRESSIVE RESEMBLANCE 339 



prevent them from being seen by their victims before they have 

 come within range. Other species exhibit even more wonderful 

 adaptations both in form and colour. Thus the South African 

 Harpax tricolor sits amongst the pink and white flowers of the 

 heath, which are imitated by similarly coloured outgrowths of 

 the insect, and there awaits the approach of its unsuspecting 

 victims ; while in Mozambique the terrible Idolum didbolicum 



I 



FIG. 171. An Indian Leaf Butterfly (Kallima inachis}; A., with wings 

 expanded ; B., with wings folded ; x if. (From a photograph.) 



simulates, both in form and colour, a large flower, and thereby 

 deceives and attracts other insects in search of honey. 



It is no doubt amongst the almost innumerable species of the 

 great group Insecta that cases of highly specialized adaptation 

 for purposes of concealment or deception are most frequently 

 met with. They also occur, however, and by no means 

 uncommonly, in other groups of the animal kingdom. A 

 familiar instance is afforded by the common British spider crab, 

 now known as Macropodia rostrata, 1 of which excellent illus- 

 trations (under the name Cancer Phalangium) were given by 



1 I am indebted to my friend, the Rev. T. 11. R. Stebbing. F.R.S., for information 

 as to the correct nomenclature, &c., of this species. 



z 2 



