DARWINISM ATTACKED. 53 



Another objection which the study of the utility of col- 

 our and pattern 2T also has impressed upon me is that of the 



OVection based Can 7 m g to ^ ar f certain lines of modification, 

 on over-speciali- Classic examples are the fatal over-development 

 of the antlers of the extinct Irish stag, the un- 

 wieldiness of the giant Cretaceous reptiles, the intimate 

 identity of the halves of bilaterally symmetrical animals. 

 Let me call attention to an overdone case of "protective 

 resemblance" among the insects. It is that of the famous 

 Kallimas, the dead-leaf butterflies of the Malayan and gen- 

 eral south tropical regions. These butterflies (there are 

 several species which show the marvellous imitation) have 

 the under sides of both fore and hind wings so coloured and 

 streaked that when apposed over the back in the manner 

 common to butterflies at rest, the four wings combine to 



Kaiiima the resemble with absurd fidelity a dead leaf still 

 dead-leaf butter- attached by a short petiole to the twig or branch. 

 I say absurd, for it seems to me the resemblance 

 is over-refined. Here for safety's sake it is no question of 

 mimicking some one particular kind of other organism or 

 inanimate thing in Nature which birds do not molest. It is 

 simply to produce the effect of a dead leaf ; any dead leaf ; 

 a brown, withering leaf on a branch. Leaf-shape and gen- 

 eral dead-leaf colour scheme are necessary for this illusion. 

 But are these following things necessary? namely, an 

 extraordinarily faithful representation of mid-rib and lateral 

 veins even to faint microscopically-tapering vein tips ; a 

 perfect short petiole produced by the apposed "tails" of the 

 hind wings ; a concealment of the head of the butterfly so 

 that it shall not mar the outlines of the lateral margin of the 

 leaf ; and, finally, delicate little flecks of purplish or yellow- 

 ish brown to mimic spots of decay and fungus-attacked spots 

 in the leaf ( !) and, as culmination, a tiny circular clear 

 spot in the fore wings (terminal part of the leaf) which shall 

 represent a worm-eaten hole, or a piercing of the dry leaf 



