ENT.
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.]

Some twenty-five years ago there appeared suddenly upon certain acacia
trees at Menlo Park, California, a very destructive scale bug. It
rapidly increased and spread from tree to tree, attacking apples, figs,
pomegranates, quinces, and roses, and many other trees and plants, but
seeming to prefer to all other food the beautiful orange and lemon trees
which grow so luxuriantly on the Pacific Coast, and from which a large
share of the income of so many fruit-growers is gained. This insect,
which came to be known as the _white scale_ or _fluted scale_ or the
_Icerya_ (from its scientific name), was an insignificant creature in
itself, resembling a small bit of fluted wax a little more than a
quarter of an inch long. But when the scales had once taken possession
of a tree, they swarmed over it until the bark was hidden; they sucked
its sap through their minute beaks until the plant became so feeble that
the leaves and young fruit dropped off, a hideous black smut-fungus
crept