ARTHROPODA 91 



ating any quality, such as colour or sweetness, 

 which has originally attracted the insect to the 

 flower. While a few plants only are fertilised by 

 means of the wind, a vast majority depend en- 

 tirely upon insects for the cross-fertilisation 

 which is so necessary for the production of 

 healthy seeds. We have already alluded to the 

 part played by the earthworm in preparing the 

 soil. If the earthworm has been the ploughman 

 the insect has been the more intelligent gardener, 

 who has filled the world with bright flowers. The 

 earlier forms of plant life had green and incon- 

 spicuous flowers (Cryptogamia) ; the Phanero- 

 gamia, or showy-flowered plants, including all 

 those that bear what are popularly termed flow- 

 ers, have been produced by the artificial selection 

 exercised by insects long before man was here to 

 admire the result, and to carry on the same work 

 in his gardens. The insect owes its food to the 

 plant world ; the plant world owes health and 

 beauty to the constant ministration of the insect; 

 so marvellous is the inter-connexion of one form 

 of life with another. 



The number of different kinds of insect is 

 enormous ; the number of named species has 

 been estimated at nearly a quarter of a million. 

 It is therefore no wonder that entomology, the 

 study of insects, has claimed the rank of a special 

 science. We cannot here' do more than refer in 

 passing to a few of the more familiar types. 

 First of all, by right of its work in fertilising 

 flowers, let us take the Bee. Fig. 25 shows its 

 honeycomb and its larvae. The bee-grub differs 

 from the caterpillar in its comparative helpless- 

 ness. It is fed like a child by the worker bees, 

 which are undeveloped females; and it does not 



