( Ixiii ) 



given by Mr. Mai^shall of the behaviour of a kestrel (Cerchneis 

 riqncoloides) when given a large Buprestid beetle {Psiloptera 

 valens) : the bird took it with apparent pleasure and en- 

 deavoured to hold it with its foot and eat it, but after a peck 

 or two it slipped from its grasp : the experiment was repeated 

 several times with the same result : the torpedo-like shape 

 and hard and slippery integument appear to prevent the 

 destruction of the insect by any bird which cannot swallow 

 it entire: baboons, however, readily ate all species of 

 Psilojjtera. 



3. Aposematic or warning coloration, including warning 

 attitudes and warning sounds : moreover, as it is plain from 

 what has been already said, that all species with warning 

 colours are largely tasted by young birds, at all events before 

 being avoided, there must always be some unpleasant odours or 

 juices present in all aposematically-coloured insects which are 

 not mimicking species : without these warning colours would 

 have no significance, for all insects possessing them, instead 

 of having been supported and increased by natural selection, 

 would have been promptly and rapidly eliminated. 



I have before said that we know nothing of the tastes of 

 the lower animals ; scents such as those of Aromia and Calli- 

 cliroma which are agreeable to us, may be nauseous or even 

 harmful to insect-eaters ; as bearing upon this it is worthy of 

 mention that Mr. Shelford has noticed that certain of the 

 Callichrominaj are the only representatives of the Longicorns of 

 Borneo, with the exception of the Clythur, which are mimicked 

 by other distantly-related Longicorns. Mimicry of this sort 

 appears invariably to prove distastefulness on the part of the 

 mimicked species. 



Again, warning attitudes have usually some effective means 

 of defence to back them up ; thus the lurva of the Puss Moth 

 can eject strong formic acid, and Ocypus olens can inflict a 

 severe bite if its terrifying attitude is disregarded : occasion- 

 ally, however, an insect appears to depend entirely upon its 

 appearance, as in the case of larvae which resemble snakes, and 

 in such cases there is really no need for ulterior means of 

 defence ; Mr. Marshall has procured most striking evidence 

 as to the alarm shown by baboons on being offered the larva 



