LONGLEY'S HYPOTHESIS 239 



from a flower by the fingers, while the utmost caution 

 is necessary if one wishes to catch the mimic ? Dr. 

 Longley lays stress on the assertion that " colour and 

 habit are associated variables," which hardly seems to 

 be consistent with the great dififerences in habit between 

 model and mimic of the same colour and pattern.^ 



Again, I would point out that it is difficult in the 

 extreme to think of all larvae, for example, as concealed 

 by likeness to their surroundings. On our common 

 hawthorn bush, for instance, caterpillars of the gold 

 tail moth, or of the " Figure of eight " moth {Diloba 

 caeruleocephala) thrust themselves upon one's notice, 

 and side by side on the same bush highly modified 

 Geometrid larvae are only to be discovered by careful 

 search, so similar are they to twigs. A large Hypsid 

 larva (pactolicus) abounded on a papilionaceous plant 

 growing on sandy shores of the islands of Lake Victoria. 

 It was marked with alternate rings of dead black and 

 purest Chinese white, with red head and legs and long 

 black or white hairs, and was visible clearly from as 

 far away as a creature of that size could be visible. It 

 developed into a gorgeous orange moth, with blue-black 

 blotches on the fore wings and a black border to the hind 

 wings, which was a brilliant and conspicuous object at 

 rest or on the wing. It freely exposed itself, and was 

 of sluggish habits and slow, heavy flight, as it would be 

 expected to be on the Darwinian explanation. Yet 

 Dr. Longley would have us believe that it is really con- 

 cealed, and offers no consistent explanation of its habits. 



The great attention that is nowadays being paid to 

 the principles of heredity as expounded first by Mendel, 

 and to the theory of " Mutations," has resulted in 

 attempts to account for cases of mimetic likeness by sup- 



^ In the case of the Lycidas the larvae are carnivorous and live in the 

 open ; those of a very close Longicorn mimic live in dead wood. At 

 the stages when the future similar colours of the adults are being pre- 

 pared the habits of model and mimic are as dissimilar as possible.. 



