xvi 



LltST OF ILLUSTRATIONS. 



PAGE 



Fig. 73. — Tracing of the middle zone of a humming-bird moth . 190 



Fig. 74. — Tracing of the course of a wasp's wing showing the upper 



part of the curve 190 



Fig. 75. — Tracing of the course of a wasp's wing : lower loops . 191 



Fig. 77. — Tracing obtained from a bee's wing in a plane tangential 



to the cylijider 192 



Fig. 78 and 79. — Tracing of a wasp's wing, compared with a "Wheat- 

 stone's rod 192, 193 



Fig. 80.— Tracing of the wing of a humming-bird moth (lower 



border) 193 



Fig. 81. — Tracing of the wing of a tired humming-bird moth . . 194 



Tracings of the Flight of Birds. 



Fig. 95. — Myographical tracing to determine the frequency of the. 



strokes of the wing in different species . . . . 232 

 Fig. 96. — Differences of frequency and of amplitude in the strokes 



of a pigeon's wing 234 



Fig. 105.— Tracing of different movements of the pigeon's wing . . 253 

 Fig. 106-107. — Construction of the trajectory of a pigeon's wing, 254, 255 

 Fig. 110. — Simultaneous tracing of the different movements of a 



buzzard's wing 262 



Fig. 111. — Inclination of the plane of the wing, with reference to the 



axis of the body during flight 263 



Fig. 113. — Vertical oscillations of the bird during flight . . . 266 

 Fig. 114. — Relation of oscillations with muscular acts . . . 268 

 Fig. 115. — Simultaneous tracing of two kinds of oscillation in the 



buzzard 271 



TRAJECTORIES. 



Fig. 23. — Attempt to illustrate, by means of a metallic wire, the 



sinuous trajectory passed through by the pubis . .119 

 Fig. 71. — Appearance of a wasp the tips of whose wings have been 



gilded 187 



Fig. 86. — Trajectory of an insect's wing 201 



Fig. 100.— Elliptical course of the point of a bird's wing . . . 242 

 Fig. 76.— Tracing of a vibrating Wheatstone's rod .... 191 



Fig. 79. — Do. tipped with a wasp's wing 193 



Fig. 101. — Ellipse traced by a Wheatstone's red on a revolving 



cylinder 243 



