MOMENTS OF CONVERGENCE 55 



both form and colour of a mimic harmonise 

 with its model, there must still be some slight 

 movement, some particular action or habit to 

 complete the illusion. Thus, to take one example 

 only as the type of a long series, there occurs 

 in Ceylon a longicorn beetle, Callichroma chryso- 

 gaster, sufficiently rare to satisfy Wallace's con- 

 dition that the imitators are always less numerous 

 than the imitated, which shows characteristic 

 waspish marks, orange yellow antennae and legs 

 set upon a body uniformly bluish black above ; 

 but it only resembles a wasp when it is in flight 

 and at the moment of alighting on a bush in full 

 sunlight ; when pinned in a box it is a " mere 

 beetle." 



Amongst insects especially there are many 

 examples of forms belonging to different orders, 

 protected by different noxious secretions, and 

 yet possessing common warning colours, which 

 do not occupy identical stations. Thus a Reduviid 

 bug living under dry bark may resemble a Bom- 

 bardier beetle living under damp logs. This 

 belongs to Poulton's category of synaposematic 

 resemblances "such as obtain between animals 

 of all kinds adopting sematic [signalling] methods 

 of defence in the same country " ; this is some- 

 times known as Miillerian mimicry, as dis- 

 tinguished from true or Batesian mimicry. The 

 common cryptic or protective coloration of many 

 animals (oceanic, deserticolous, lichenicolous) in 



