32 THE WONDER OF LIFE 



things is mimicry in the strict sense, where there is a striking 

 external resemblance between two unrelated animals which 

 frequent the same haunts. As examples we may cite the re- 

 semblance between the drone-fly (Eristalis) and a bee ; 

 between the European grass-snake, Tropidonotus viperinus, 

 quite innocent in character, and a viper ; between the Lepi- 

 dopteron Trochilium apiforme and the hornet ; between a 

 spider (e.g. Myrmarachne formicaria] and the dreaded ant. 



It is usual to refuse the title of true mimicry unless it 

 can be shown (or unless it has been shown in analogous 

 cases) that the mimicker lives along with the mimicked 

 to a considerable extent, that the mimickers are in the 

 minority, that the mimickers are like the mimicked in 

 superficial characters only, and that the mimicked are 

 more or less markedly safe and usually more or less con- 

 spicuous. It goes without saying that the use of the terms 

 mimicker and mimicked is entirely metaphorical, for the 

 mimetic resemblance is not deliberate. 



Students of mimicry are accustomed to distinguish several 

 types. Thus in ' Batesian Mimicry ', first clearly defined by 

 the naturalist-traveller Bates, we have a palatable animal 

 escaping in virtue of its superficial resemblance to unpalat- 

 able forms, with striking features, which are rarely attacked 

 and are greatly in the majority over the mimickers. The 

 bad reputation of ants gives a vicarious safety to several 

 ant-like spiders ; the disagreeable taste of the mimicked 

 butterfly helps the survival of its palatable Doppel- 

 Ganger. 



Mr. Guy A. K. Marshall observed a Dipterous fly, Ceria 

 gambiana, visiting flowers in company with a formidable 

 wasp, Polistes marginalis, and it seems reasonable to infer 

 that the fly profits by its likeness to the dangerous creature 



