_Anas boschas_, 347. Anatomy defined, 3. _Anguilla_, 284. _Anguillula_, 140. _Anolis principalis_, 319. _Anosia plexippus_, anatomy of larva of, 177; external structure of, 171, *172; life of, 175; mimicked by _Basilarchia archippus_, *433. Anseres, 347. Ant, little black, *224; little brown, 223. Antelope, *395, 396. Antenna of carrion beetle, *184. _Antilocapra americana_, *395, 396. _Antrostomus vociferus_, 356. Ant, 212, 218, 223. Anura, 299. Ape, 401. Aphidiæ, 200. _Apis florea_, comb of, *222. _Apis mellifica_, *218. Appearance, terrifying, 430. Aquarium, 457. Aquarium, battery-jar, *461. _Aquila chrysætos_, 342. Arachnida, 144, 229. _Arctomys monax_, 391. _Ardea herodias_, 358. _Ardea virescens_, 347. _Argiope_ sp., *236. Argonaut, 257. _Argonauta argo_, 257. _Ariolimax californica_, *252. Arthogastra, 230. Arthropoda, 144. Ascidian, 259, *261. _Aspidiotus aurantii_, *198. _Asterias_ sp., structure and life of, 108. _Asterias_, *109; cross-section of, *112. _Asterias ocracia_, *122. _Asterina mineata_, *122. Asteroidea, 120, 121. Attidæ, 235. Auk, great, 345. Aves, 327. _Aythya vallisneria_, 347. Ayu, 283. Back-swimmer, 197, 199. _Balanus_, *153. _Balæna glacialis_, 393. _Balæna mysticetus_, 393. Barbadoes earth, 82. Barnacle, *153, 155; sessile, 155; stalked, 155. Barn-owl, 353. _Bartramia longicauda_, 349. _Bascanium constrictor_, 321. Bass, 282. Bat, hoary, *392. Batrachia, 291. Batrachians, 291; body form and structure of, 292; classification of, 295; life-history and habits of, 295; structure of, 292. Bat, 391. Bead-snake, 322. Bear, 398. Beaver, 391. Bed-bug, *188. Bee, 212; solitary, 216. Beetle, great water-scavenger, 163; external structure, *164; internal structure, *167; antenna of carrion, *184; Colorado potato, 209. Beetle, 206; carrion, 209; whirligig, 206. Bell-animalcule, structure and life of, 75. Bills of birds, 362. Bipinnaria, 119. Bird, frigate, 346; man-of-war, 346; outline of body showing external regions, *330; ruby-throat humming, nest and eggs of, *357. Bird-louse, *194. Birds, 327; bills and feet of, 362; body form and structure of, 336; care of young, 366; classification of, 340; collecting, 466; determining, 359; development and life-history of, 339; feeding habits of, 370; flight and songs of, 364; migration of, 367; molting of, 361; nesting of, 366; protection of, 370. Bird-skins, making, 466. _Bison bison_, 396, *397. Bittern, 348. Blacksnake, 321. _Blissus leucopterus_, 198. Blood, circulation of, in mammal, *376. Blood of toad, structure of, 40. Blow-fly, 201, 202; section through compound eye of, *185.