84 THE ENTOMOLOGIST. 



flight gave me the idea that the insect had the least notion as to 

 where it was going. Generally their movements seem purpose- 

 less. Nevertheless some species, including the Fritillaries, are 

 fairly methodic. Among the high Alps of the Canton Grisons, 

 however, where some of my observations have been made, there 

 are very few bees when compared with what we have in England, 

 whilst the number of butterflies and moths is so great that 

 it hardly bears comparison with the number here. I presume, 

 therefore, that a large number of plants growing on the Alps are 

 fertilized by Lepidoptera, although I have only a very few 

 observations to that effect, as insects of this class are most 

 difficult and unsatisfactory to watch. 



We have now seen that insects do possess a decided preference 

 for a number of successive visits to the same species of flower, 

 although this is not invariably the case. It is quite needless 

 here to treat of the great importance of this fact to the plants 

 themselves, or of the numerous variations and modifications of 

 colour, form, scent, and other particulars which the plants 

 appear to have effected in their flowers with a view of inducing 

 the insects to be thus methodic in their habits. I cannot doubt 

 that Mr. Darwin is right when, in speaking of the probable 

 reasons why insects are methodic, he says (' Cross- and Self- 

 fertilization of Flowers,' p. 419): — "The cause probably lies 

 in the insects being thus enabled to work quicker ; they have 

 just learnt how to stand in the best position on the flower, 

 and how far and in what direction to insert their proboscides. 

 They act on the same principle as does an artificer who has 

 to make half a dozen engines, and who saves time by making 

 consecutively each wheel and part for all of them." 



Although so little is really known as to the sight of insects, 

 Sir John Lubbock's observations have satisfactorily established 

 the fact that bees can distinguish some at least of the colours, 

 and that they show a preference for blue. Colour, however, 

 is not the only sense which guides insects from one flower to 

 another of the same species, although I believe it largely does so. 

 Some other sense must have been called into use in observation 

 No. 43, where a small humble-bee visited 15 flowers of Digitalis 

 'purpurea, some being white and others coloured ; in observation 

 No. 57, where a specimen of Pieris brassica visited flowers of 

 Geranium which were both scarlet and pink ; and in observation 



