426 tfflE ZOOLOGIStf. 



variety had been crossed in the earlier generations it would have 

 been lost : — 



"Florists may learn from the four cases which have been 

 fully described that they have the power of fixing each fleeting 

 variety of colour, if they will fertilise the flowers of the desired 

 kind with their own pollen for half-a-dozen generations, and 

 grow the seedlings under the same conditions. But a cross with 

 any other individual of the same variety must be carefully pre- 

 vented, as each has its own peculiar constitution." 



The contrast between the bee of nature and the bee required 

 to give permanence to an incipient species is obvious. And, as 

 far as my observations go, there are no blue flowers more 

 frequently visited by bees than are many of other colours, — 

 white, yellow, greenish, pink, &c. Indeed, some uncompro- 

 misingly green flowers seem to be rather favourites, e.g., plane 

 tree, red currant, and raspberry. 



" The flowers of a species of Trianosperma in South Brazil are 

 visited, according to Fritz Muller, very abundantly all day long 

 by Apis mellifica and species of Melipona, although they are 

 scentless, greenish, quite inconspicuous, and to a great extent 

 hidden by foliage. If the bees of to-day, in the midst of flowers 

 of every hue, are content at times to take their honey from 

 green flowers, is it reasonable to suppose that the bee of former 

 ages would neglect them?"* Moreover, there are some bright 

 blue flowers which they do not visit frequently, such as peri- 

 winkle, Lobelia, and hairbell. 



With regard to the periwinkle, the bee is apparently some- 

 what erratic. H. Muller, for example, states that he has seen 

 Vinca minor abundantly visited by insects, and gives a list which 

 includes seven species of bees. But he also informs us that 

 other well-known observers — Sprengel, Darwin, Delphino, and 

 Hildebrande— seem never to have seen any insects upon it but 

 thrips. And on Vinca major — which differs from V. minor 

 chiefly in size — he has once seen Bombus agrorum ! For my 

 own part, I think I have seen bees on the periwinkle on one or 

 two occasions. 



With regard to Lobelia, the bee — so far as my observations 

 go — is extremely irregular. I watched them for several years 



* H. Muller, ' Fertilisation of Flowers.' 



