Mimicry 345 



established, so to say, a reputation for disagreeable taste. It 

 has been impossible to decide whether, as a matter of his- 

 torical fact, the mimics did actually arise in an area in which 

 the model forms were prevalent. At the present time, 

 however, we find that although two such " resembling " 

 forms frequently occupy the same or overlapping areas, at 

 other times they live in totally separate areas. 



3 



4 



Fig. 87. Mimicry among Hover Flies 



A bumblebee (Bombus pennsylvanicus) , i, is supposed to 

 be " mimicked " by the hover fly (Laphria thoracica) , 2. In 

 the same way, the wasp (Vespa maculata) , j, is imitated by 

 the hover fly (Spilomyia fusca), 4. Striking cases of mim- 

 icry are found in ail parts of the world, sometimes under 

 circumstances that do not permit the usual interpretation of 

 advantage to the mimic, or of some influence of the model in 

 the development of the pattern. From Gruenberg, Elemen- 

 tary Biology, published by Ginn & Company. 



One remarkable example of the latter condition is fur- 

 nished by the group of flies, the Syrpbidce, in southern Japan. 

 Flies of this family are exceptionally numerous and are also 

 remarkably similar in their general appearance and move- 

 ments to certain insects that belong to the bee and wasp 

 order (Fig. 87). Moreover, the flies hover about flowers 

 and have in relation to the plants precisely the same effect 

 as bees would have, that is, in the distribution of pollen. 



