will adopt your conclusions." We take our time from the geologists and physicists, and it is monstrous that, having taken our time from the physical philosopher's clock, the physical philosopher should turn round upon us, and say we are too fast or too slow. What we desire to know is, is it a fact that evolution took place? As to the amount of time which evolution may have occupied, we are in the hands of the physicist and the astronomer, whose business it is to deal with those questions. [Illustration: Fig. 9] Fore Foot. Hind Foot. Fore-arm. Leg. Upper Molar. Lower Molar. RECENT. EQUUS. PLIOCENE. PLIOHIPPUS. PROTOHIPPUS (_Hipparion_). MIOCENE. MIOHIPPUS (_Anchitherium_). MESOHIPPUS. EOCENE. OROHIPPUS. FOOTNOTES: [5] I use the word "type" because it is highly probable that many of the forms of _Anchitherium_-like and _Hipparion_-like animals existed in the Miocene and Pliocene epochs, just as many species of the horse tribe exist now; and it is highly improbable that the particular species of _Anchitherium_ or _Hipparion_, which happen to have been discovered, should be precisely those which have formed part of the direct line of the horse's pedigree. [6] Since this lecture was delivered, Professor Marsh has discovered a new genus of equine mammals (_Eohippus_) from the lowest Eocene deposits of the West, which corresponds very nearly to this description.--_American Journal of Science_, November, 1876. FIGHTING PESTS WITH INSECT ALLIES LELAND O. HOWARD [Dr. Howard is Chief of the Division of Entomology in the United States Department of Agriculture at Washington. He is a lecturer at Swarthmore College and at Georgetown University. He has written "The Insect Book," published by Doubleday, Page & Co., New York; and a work on Mosquitoes, issued by McClure, Phillips & Co., New York. Both are books of interest from the hand of a master: they are fully illustrated. The narrative which follows appeared in _Everybody's Magazine_, June, 1901.]