14. Yucca Flower and Moth 83 15. Newly-hatched Chick swimming. (Drawn by Mr. Charles Whymper, after instantaneous photographs and a sketch by the author) 85 16. Nestling Megapode. (From Dr. R. Bowdler Sharpe’s “Wonders of the Bird World.” Wells Gardner) 87 17. Cuckoo ejecting Meadow Pipit. (From Mrs. Hugh Blackburn’s sketch in “Birds from Moidart.” David Douglas) 91 18. Leaf-case of Birch-weevil 121 19. Solitary Wasp using a stone as a tool. (After Plate V. in Dr. Peckham’s “Solitary Wasps”) 127 20. Spiders placed by Solitary Wasps in crotches of branching stems. (After Plate X. in Dr. Peckham’s “Solitary Wasps”) 133 21. Fox-terrier lifting the latch of a gate. (Drawn by Mr. Charles Whymper, after a photograph by Miss Alice Worsley) 145 22. Cage used by Dr. Thorndike. (After figure in “Animal Intelligence,” _Psychological Review_, 1898) 148 23. Diagram illustrating Dr. Thorndike’s Experiments. (Based on data given in his monograph on “Animal Intelligence”) 150 24. Wood ant. (From Shipley’s “Invertebrates.” A. & C. Black) 207 25. Beetle soliciting food from Ant. (After Wasmann. Enlarged) 213 26. Honey-pot Ant. (Enlarged) 215 ANIMAL BEHAVIOUR CHAPTER I _ORGANIC BEHAVIOUR_ I.--BEHAVIOUR IN GENERAL We commonly use the word “behaviour” with a wide range of meaning. We speak of the behaviour of troops in the field, of the prisoner at the bar, of a dandy in the ball-room. But the chemist and the physicist often speak of the behaviour of atoms and molecules, or that of a gas under changing conditions of temperature and pressure. The geologist tells us that a glacier behaves in many respects like a river, and discusses how the crust of the earth behaves under the stresses to which it is subjected. Weather-wise people comment on the behaviour of the mercury in a barometer as a storm approaches. Instances of a similar usage need not be multiplied. Frequently employed with a moral significance, the word is at least occasionally used in a wider and more comprehensive sense. When Mary, the nurse, returns with the little Miss Smiths from Master Brown’s birthday party, she is narrowly questioned as to their behaviour; but meanwhile their father, the professor, has been discoursing to his students on the behaviour of iron filings in the magnetic field; and his son Jack, of H.M.S. _Blunderer_, entertains his elder sisters with a graphic description of the behaviour of a first-class battle-ship in a heavy sea.