THE STRUCTURE AND LIFE OF INSECTS 251 



ready for the purpose. One thing which makes us believe 

 that the honey is not digested before being disgorged is 

 that it differs so much according to the plants from which 

 it has been obtained. Clover, heather, orange-blossoms, 

 labiate flowers (mint, rosemary and the like) affect the 

 taste, smell, colour and consistency of the honey ; honey 

 from poisonous flowers is sometimes itself poisonous. Such 

 differences would not be likely to occur if the honey had 

 been really digested. 



How did plants come to make honey ? The possibility 

 of such a thing arose when green plants found out how 

 to decompose carbonic acid in presence of sunlight. Sugar 

 then appeared in the cells, and was ready to be excreted 

 whenever a sufficient reason should exist. Various parts 

 of green plants exude sugar (leaves, leaf -stalks, &c.), and 

 the next step, viz. the exudation of sugar at the base of 

 the floral leaves, is not a very great one. If insects, 

 attracted to the flower by the hope of pollen, happened 

 to find honey as well, that would be a powerful motive 

 for coming again. The flowers which had secreted the 

 honey would get their seeds fertilised more readily than 

 others, and thus would be founded that alliance between 

 flowers and insects, which is now so well established that 

 many flowers cannot set their seeds at all if insects are kept 

 off by a muslin net. It only remained to bring the 

 mechanism to perfection. The honey became more 

 abundant, exuded only at the time when the pollen was 

 ready for transference, and was not only protected more 

 and more carefully from rain and marauders, but placed 

 just where it would ensure fertilisation. The perfume, 

 which is so powerful an aid in attracting insects, is usually 

 only the perfume of the honey itself. 



The insects on their side acquired an increased appetite 

 for honey and increased expertness in finding it ; their 

 crops enlarged ; they learned how to make store-houses 

 for their honey, using first of all, it may be, natural cavities, 

 then cells of earth, clay, or impure pollen, and lastly cells 



