Cuckoo, 71, 72, 87; solemnity, 88; nesting, 88, 89; young, 89; nest, 90; food, 90. Cuckoo, black-billed, notes, 87, 88; nesting-habits, 88. Cuckoo, yellow-billed, 87. Dana, Richard Henry, Jr., at San Diego, 210, 211. Darwin, Charles, quoted, 5,17, 18, 33; his eager study of natural history, 17, 18; observations during the voyage of the Beagle, 18, 19; failure of his theory, 147, 167-69; his mind, 173; treated man as an animal, 174. Darwin, George Howard, on the tides, 169, 170. Darwinism, a cause of the World War, 172-75. Death, an analogy of, 185, 186. Desert, vegetation of the, 143-48. Dove, mourning, _or_ turtle-dove, 86. Earth, the, quiverings of the surface, 169-71; the Northern and Southern Hemispheres, 171, 172. Edison, Thomas A., 114, 119; contrasted with Mr. Ford, 122-25. Elm, autumn color, 3. Emerson, Ralph Waldo, quoted, 69, 165, 186. Erosion, as sculpture, 181-83. Fabre, Jean Henri, 162; quoted, 139. Far-away, the, 39. Fear in animals, 58, 59, 154, 155, 209. Fireflies, 19. Firestone, H. S., 119, 125. Fish, schools of, 154. Fleas, 210. Flies, intelligence, 156, 157. Foraminiferæ, 194. Ford, Henry, 113, 114, 119, 120; contrasted with Mr. Edison, 122-24. Foxes, 180. Frog, wood, 94, 95. Germans, Darwinism, and the World War, 172-75. Giraffe, 200. Girls, two West Virginia, 115. Gnatcatcher, blue-gray, 103. God, man appropriating, 199. Goldfinch, flight, 37, 42; chorus singing, 40-42; notes, 42; notes of young, 43; nesting, 43. Grand Cañon, 182, 194. Grass, the wonder of, 74, 75. Grasshoppers, 155. Great Smoky Mts., 109. Greensborough, Pa., 112. Grosbeak, rose-breasted, nesting, 65. Grouse, ruffed, 166. Gull, herring, 131. Gulls, flight, 38. Hawk, red-tailed, 32. Hawks, flight, 35. Haymaking, 69-76. Hen-hawk, flight, 35. Hornets, 163. Horns, 201, 202. Horse, 205, 206. Horseshoe Run, W. Va., 114. Hummingbird, ruby-throated, 64; bathing in dew, 13; nest, 79; a fairy bird, 94. Hurley, Edward N., 113. Huxley, Thomas Henry, 27; quoted, 8, 25. Ibis, white, 32, 153, 154. Insects, their world, 23-25, 162; senses, 24; reaction to heat, cold, and vibrations, 25; antennæ, 25; the ruling sex among, 140, 141. Interpretation, 186-90. Ironweed, 116. James, William, 22. Jay, blue, notes, 87. Joe-Pye-weed, 116. Junco, young, 19, 20; nesting, 81; abundance, 82. Kepler, Johann, 169. Killdeer, 130, 131. Kingbird, flight, 37; and bees, 156. Leaves, autumn, 1-3. Lemmings, 152, 153. Life, origin of, 194, 195. Life, human, analogies, 25-27. Lightning-bugs. _See_ Fireflies. Lowell, James Russell, quoted, 5. Lubbock, Sir John, quoted, 156. McCarthy, Denis Aloysius, quoted, 157.