XVI LIST 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 cylinder 192 



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

 stone's rod . 192, 193 



FIG. SO. 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 tl\e 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 

 Fio. 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 .... l;i] 



FIG. 79. Do. tipped with a wasp's wing l'.i:j 



FIG. 101. Ellipse traced by a WlieatM<nu-'s r< d on a revolving 



cylinder 243 



