rvations of a sick, 102.

FROG, tinctumutation in the, 182;
chromatophores of, 182;
Heincke's observations, 183;
location of color-changing sense in, 190.

G

GADFLY, selection of suitable spot for oviposition by, 103.

GILT CATFISH, _gyropeltes_ make the toilet of, 130;
color-changing in, 183;
author's experiments on the color-changing function of, 191.

GOBIUS RUTHENSPARRI, tinctumutation in, 183.

GOGGLE-EYE PERCH, love of offspring in, 138;
homing sense in, 200.

GOOSE, homing sense in the, 199.

GORILLA, use of cudgel by, 222.

GRASSHOPPER, ears of, 30.

GYRINUS, indifference to seasons shown by, 23;
eyes of, 24.

GYROPELTES, health of gilt catfish dependent on, 130.

H

HELICONIDAE, length of life in, 138.

HELIX POMATIA, love of amusement in, 123;
author's observations, 124.

HEMIPTERA, organs of audition in, 29.

HOG, friendship between a dog and a, 81.

HONEY BEE, recognition of impending calamity by, 90;
consternation and dismay manifested by, 90;
remarkable engineering feat by, 91;
joy evinced by, 91;
grief shown by, 91, 92;
Huber's experiment demonstrating reason in, 178.

HORSE, love of offspring in the, 143;
seeking man's aid when in trouble, 144;
self-medication by, 220.

HOUND, death-feigning by, 212.

HUMMING-BIRD, decorative instinct in, 128.

HYDRA, water-louse feeding on the buds of, 52.

HYDROZOA, nerve-tissue in, 41.

HYMENOPTERA, recognition of kindred in social, 69.

I

ICHNEUMON, method of ovipositing in the bodies of caterpillars used
by, 104.

INSTINCT, definition of, 147, 148.

J

JAY, parental love in the, 142;
battle between cat and, 143.

JELLY-FISH, anatomy, physiology, and psychology of, 4;
nerve-ring in nectocalyx of, 5;
"eyes" of, 5;
manubrium or "handle" of, 5;
sensitiveness of nervous system in, 5;
pulsing of nectocalyx in, 5;
intoxicated, 15;
light sought by, 15;
effect of the excision of the marginal bodies of, 52;
conscious determination in, 52;
effect of alcohol on, 219.

K

KATYDID, color-changing function in, 191, 192.

L

LAND TERRAPIN, memory of locality in, 65;
homing sense in, 65;
author's experiments with, 65.

LASIUS FLAVUS, author's experiments with, 67;
slow in recognizing kin, 67;
ants of the same species disinter buried, 101.

LASIUS NIGER, memory of kindred in, 66.

LEPIDOPTERA, organs of hearing in, 35.

LETISIMULATION, defini