OUR DEBT TO INSECTS. 333 



ing hills of our familiar Europe, we should probably see the interior 

 country composed only of low ridges, unlifted as yet by the slow up- 

 heaval of ages into the Alps or Pyrenees of the modern continent. 

 But the most striking peculiarity of the scene would doubtless be the 

 wearisome uniformity of its prevailing colors. Earth beneath and 

 primitive trees overhead would all alike present a single field of un- 

 broken and unvarying green. No scarlet flower, golden fruit, or gay 

 butterfly would give a gleam of brighter and warmer coloring to the 

 continuous verdure of that more than tropical forest. Green, and 

 green, and green, again ; wherever the eye fell it would rest alike 

 upon one monotonous and unrelieved mass of harsh and angular 

 verdure. 



On the other hand, if we turn to a modern English meadow, we 

 find it bright with yellow buttercups and purple clover, pink-tipped 

 daisies and pale-faced primroses. We see the hedges white with may 

 or glowing with dog-roses. "We find the trees overhead covered with 

 apple-blossom or scented with horse-chestnut. While in and out 

 among the beautiful flowers flit equally beautiful butterflies — emper- 

 ors, admirals, peacocks, orange-tips, and painted ladies. The green 

 of the grassy meadow and the blue of the open sky serve only as back- 

 grounds to show off the brighter hues of the beautiful blossoms and 

 the insects that pay court to them incessantly. 



To what is this great change in the general aspect of nature due ? 

 Almost entirely, we may now confidently conclude, to the color-sense 

 in the insects themselves. The lovely tints of the summer flowers 

 and the exquisite patterns on the butterfly's wings have alike been 

 developed through the taste and the selective action of these humble 

 little creatures. To trace up the gradual evolution of the insect color- 

 sense and its subsequent reactions upon the outer world, we must go 

 back to a time when neither flower nor butterfly yet existed. 



In the carboniferous earth we have reason to believe that almost 

 all the vegetation belonged to the flowerless type — the type now rep- 

 resented among us by ferns and horse-tails. These plants, as every- 

 body knows, have no flowers, but only spores or naked frondlets. 

 There were a few flowering plants it is true, in the carboniferous 

 world, but they belonged entirely to the group of conifers, trees like 

 the pines and cycads, which bear their seeds in cones, and whose flow- 

 ers would only be recognized as such by a technical botanist. Even 

 if some stray archaic members of the true flowering groups already 

 existed, it is, at any rate, almost certain that they must have been 

 devoid of those gay petals which distinguish the beautiful modern 

 blossoms in our fields and gardens. 



A flower, of course, consists essentially of a pistil or seed-produc- 

 ing organ, and a certain number of stamens or fertilizers. ISTo seed 

 can come to maturity unless fertilized by pollen from a stamen. But 

 experience, and more especially the experiments of Mr. Darwin, have 



