more economically, especially the more highly organized and industrious ones. In a few instances hummingbirds, as well, unwittingly do the flower's bidding while they feast now here, now there. In spite of Sprengel's most patient and scientific research, that shed great light on the theory of natural selection a half century before Darwin advanced it, he never knew that flowers are nearly always sterile to pollen of another species when carried to them on the bodies of insect visitors, or that cross-pollenized blossoms defeat the self-pollinated ones in the struggle for survival. These facts Darwin proved in endless experiments. Because bees depend absolutely upon flowers, not only for their own food but for that of future generations for whom they labor; because they are the most diligent of all visitors, and are rarely diverted from one species of flower to another while on their rounds collecting, as they must, both nectar and pollen, it follows they are the most important fertilizing agents. It is estimated that, should they perish, more than half the flowers in the world would be exterminated with them! Australian farmers imported clover from Europe, and although they had luxuriant fields of it, no seed was set for next year's planting, because they had failed to import the bumblebee. After his arrival, their loss was speedily made good. Ages before men cultivated gardens, they had tiny helpers they knew not of. Gardeners win all the glory of producing a Lawson pink or a new chrysanthemum; but only for a few seasons do they select, hybridize, according to their own rules of taste. They take up the work where insects left it off after countless centuries of toil. Thus it is to the night-flying moth, long of tongue, keen of scent, that we are indebted for the deep, white, fragrant Easter lily, for example, and not to the florist; albeit the moth is in his turn indebted to the lily for the length of his tongue and his keen nerves: neither could have advanced without the other. What long vistas through the ages of creation does not this interdependence of flowers and insects open! Over five hundred flowers in this book have been classified according to color, because it is believed that the novice, with no knowledge of botany whatever, can most readily identify the specimen found afield by this method, which has the added advantage of being the simple one adopted by the higher insects ages before books were written. Technicalities have been avoided in the text wherever possible, not to discourage the beginner from entering upon one of the most enjoyable and elevating branches of Nature study. The scientific names and classification follow that method adopted by the International Botanical Congress which has now superseded all others; nevertheless the titles employed by Gray, with which older botanists in this country are familiar, are also indicated where they differ from the new nomenclature. NELTJE BLANCHAN, New York, March, 1900