A NATURALIST IN BRAZIL 



perceive odours at such a distance that a flower is able to attract 

 species of insects which otherwise one would never see. It has been 

 ascertained that bees are able to scent the flowers of the wild vine — 

 which for us are quite without perfume — at a distance of 300 yards ; 

 and if a female Peacock moth, who has no scent that our nostrils 

 can detect, is placed in a cage, she will attract, in the course of the 

 night, numbers of male moths, although these are by no means 

 common. And according to the nature of their visitors, the flowers 

 give off their scent by day or by night ; indeed, the intensity of their 

 scent varies at different hours of the day. 



In Ceylon, one day, as I was walking through the botanical 

 gardens of Peradeniya, I suddenly drew back before a horrible 

 stench of putrefying flesh which filled the air. Looking up, I saw 

 flowers as big as a man's head hanging from a creeper-covered 

 arch (Plate 18). These were the flowers of the Brazihan Aristolochia 

 grandiflora. The flower of this creeper looks like an open bag ; the 

 mouth is wide agape, and has the colour of bleeding flesh. This 

 colour, together with the carrion stench, attracts flies; they climb 

 up a long filament that hangs from the flower, reach the edge of the 

 bag, and wander into it, following the scent. But the tubular part 

 of the corolla is set with hairs pointing inwards, which prevent egress, 

 on the principle of an eel-trap. The flies, having once entered, must 

 go on and on until they reach the dilated terminal portion of the 

 flowers, which contains the stamens, as yet withholding their pollen, 

 and the ripe stigma. If the flies have been in an Aristolochia before, 

 they have pollen adhering to them ; they rub it off on to the stigma, 

 and accomplish their task of fertilization. Now the hairs of the tube 

 grow limp, and simultaneously the anthers open. The flies cover 

 themselves with pollen and creep out, to repeat the whole act in 

 the next flower they visit. Brazil has quite a number of such fly- 

 fertilized flowers, which assume the most fantastic shapes imaginable. 

 For that matter, the Arums are fertilized by flies, and possess a 

 similar mechanism. 



Just as the insects have a preference for certain odours, so they 

 are attracted or repelled by certain colours. Quite recently experi- 

 ments have been made in this connection, and it has been proved 

 beyond a doubt that insects actually fly towards certain colours, 

 even if these are represented merely by coloured strips of paper, 

 when any possibility of the co-operation of the sense of smell is 

 excluded. It has been shown that bumble-bees and hive-bees have 

 a preference for blue and violet, and other insects for yellow, while 



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