196 muller's theory of :\iutual protection. 



the situation of repeating a recently learned disagreeable 

 experience of this nature. 



Bright and conspicuous colours in insects are then a 

 source of safety rather than of danger, and the more highly 

 a distasteful caterpillar or butterfly or beetle is adorned, 

 the more easily and quickly it is recognised when once its 

 inedibility has been tested, and the greater will be its 

 chances of escaping destruction. 



IV. Mutual Protection : Miillers theory. 



There are in many parts of the world a number of 

 highly coloured and inedible butterflies of entirely 

 different sub-families and genera, which are so similar in 

 outward appearance, markings, colours, shape of wings and 

 peculiarity of flight that they may be very easily mistaken 

 one for another. 



A considerable number of cases are known in which 

 two entirely different butterflies, or a butterfly and a moth, 

 exactly alike in appearance, are found flying in concert, or 

 in the same locality. This similarity is often seen between 

 three or four different kinds, and occasionally within a 

 limited area there are found six or seven or even a larger 

 number of different species of butterflies, of two or more 

 different sub-families, in which the likeness of each to the 

 others is remarkably close ; and the probability of mistaking 

 them is especially great when the insects are on the wing. 



It was for some time a problem to students of this 

 branch of biology why this superficial resemblance amongst 

 the inedible Lepidoptera should exist, and the explanation 

 which is now accepted is due to the observations of Fritz 

 Muller. 



As the young insect-eating animals have to learn by 

 experience what food to select and what to avoid, there 

 must be a certain number of the inedible insects attacked 



