192 ME. E. M. CHRISTY ON THE METHODIC HABITS 



Ifc will be observed that uiost of my observations have been 

 made upon Bees, which seem to me to perform the fertilization 

 of at least one half of all the flowers which are fertilized by 

 insects in this country. As to Butterflies I have seldom seen 

 one whose flight gave me the idea that the insect had the least 

 notion as to where it was going. Generally their movements 

 seem purposeless. Nevertheless some sj)ecies, including the 

 Fritillaries, are fairly methodic. Among the high Alps of the 

 Canton Grrisons, however, where some of my observations have 

 been made, there are very few Bees when compared with v/hat 

 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 efiect, 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 eflected 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 Mowers,' 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 Digi- 

 talis ptioyiirea, some being white and others coloured; in obser- 



