OUR DEBT TO INSECTS, 



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which is so familiar a fashionable dinner-table plant, bears little yel- 

 low flowers which would not of themselves attract the eyes of insects ; 

 but it makes up for this deficiency by a large surrounding bunch of 

 the richest crimson leaves, whose gorgeous coloring makes the tree a 

 universal favorite with tropical bees and butterflies. The lovely bou- 

 gainvillea carries the same idea one step further, for its small flowers 

 are inclosed by three regularly arranged bracts of a delicate mauve or 

 pink ; and, when one sees a tree covered with this magnificent creeper 

 in full blossom, it forms one of the most glorious masses of color to 

 be found in the whole of external nature. Many tropical plants, and 

 especially those of parasitical habit, are much given to developing 

 these extra allurements of colored leaves, and their general effect is 

 usually one of extreme brilliancy. From all these examples, we can 

 draw the conclusion that color does not belong by original nature to 

 one part of the plant rather than another ; but that wherever the col- 

 ored juices which result from oxidation of chlorophyl and its ana- 

 logues began to show themselves, in the neighborhood of the stamens 

 and pistil, they would attract the attention of insects, and so grow 

 more and more prominent, through natural selection, from generation 

 to generation, till they finally attained the present beauty of the tulip, 

 the rose, the poinsettia, and the bougainvillea. 



From this marvelous reaction of the color-sense in insects upon 

 the vegetal world we must next pass on to its reaction upon the hues 

 of insects themselves. For we probably owe the exquisite wings of 

 the butterfly and the gorgeous burnished bronze of the rose-beetle to 

 the very same sense and the very same selective action which have pro- 

 duced the hues of the lily and the hyacinth. What proofs can be 

 shown that the colors of insects are thus due to sexual selection ? In 

 the first place, we have the certain fact that bees at least, and prob- 

 ably other insects, do distinguish and remember colors. Not only so, 

 but their tendency to follow color has been strong enough to produce 

 all the beautiful blossoms of our fields and gardens. Moreover, we 

 have seen that while bees, which are flower-haunters, are guided great- 

 ly by color, wasps, which are omnivorous, are guided to a less extent, 

 and ants, which are very miscellaneous feeders, not at all. It may be 

 objected that insects do not care for the color apart from the amount 

 of honey ; but Mr. Anderson noticed that, when the corollas of certain 

 flowers had been cut away, the insects never discovered or visited the 

 flowers ; and Mr. Darwin lopped off the big lower petals of several 

 lobelia-blossoms, and found that the bees never noticed them, though 

 they constantly visited the neighboring flowers. On the other hand, 

 many bright -colored bells have no honey, but merely make a great 

 show for nothing, and so deceive insects into paying them a call on 

 the delusive expectation that they will be asked to stay to dinner. 

 Some very unprincipled flowers, like the huge Sumatran rafflesia, thus 

 take in the carrion-flies, by resembling in smell and appearance a 



