138 SAGACITY AND MORALIl V OF PLANTS. 



believe that a difference in odours may be of quite 

 as much importance to flowers, in guiding the proper 

 kinds of insects to them, as difference in colours has 

 proved to be. To night-opening flowers character- 

 istic perfumes must be of supremest importance ; for 

 there is no colour visible in the dark, to attract or 

 direct the attention of moths to them. 



How odours can be specialised is illustrated by 

 the Stapelias and some Arums ^ the former common 

 in green-houses. The smell given off by the flowers 

 of these plants resembles that of animal matter in 

 a "high" condition. The lurid flesh colour of the 

 flowers assists in the deceit ; and it is no unfrequent 

 thing to see them " blown " by such flesh-feeding flies 

 as our common blue -bottles. Singularly enough, 

 most of the flowers which ^w^ off fetid odours are 

 either some tint of red or on their way to it ; and 

 such are generally visited by dipterous flies, even 

 when only a faint odour is given off, if the flowers 

 are of a liver colour and little known (on account of 

 their recent introduction) to the insects of a place. 

 For instance, last summer I was particularly struck 

 with the fact that none but dipterous flies visited the 

 male and female flowers of the variegated Laurel 

 {Aucuba japonicd). For several years past, in my 

 own garden, the female plants have borne abundant 

 crops of scarlet berries. On examining the flies taken 

 from the male flowers, I invariably found their bodies 

 scattered over with the pollen -grains. The liver 



