xii TABLE OF CONTENTS 



The posterior lobe 61 



The methods of uniting the two wings of each side 61 



The hamuli 61 



The frenulum and the frenulum hook 61 



The jugum 61 



Thefibula 62 



The hypothetical type of the primitive wing- venation 62 



Longitudinal veins and cross-veins 64 



The principal wing-veins 64 



The chief branches of the wing- veins 64 



The veins of the anal area 65 



The reduction of the number of the wing- veins 65 



Serial veins 67 



The increase of the number of the wing- veins 68 



The accessory veins 68 



The intercalary veins 69 



The adventitious veins 70 



The anastomosis of veins 7 



The named cross- veins 71 



The arculus 72 



The terminology of the cells of the wing 72 



The corrugations of the wings 73 



Convex and concave veins 73 



The furrows of the wing 73 



The bullae 74 



The ambient vein 74 



The humeral veins 74 



The pterostigma or stigma 74 



The epipluras 74 



The discal cell and the discal vein 74 



The anal area and the preanal area of the wing 75 



4. THE ABDOMEN 75 



a. The segments of the abdomen 75 



b. The appendages of the abdomen 76 



The styli or vestigial legs of certain Thysanura 76 



The collophore of the Collembola 76 



The spring of the Collembola 76 



The genitalia 76 



The cerci 77 



The median caudal filament 7^ 



The prolegs of larvae 78 



5. THE MUSIC AND THE MUSICAL ORGANS OF INSECTS 78 



a. Sounds produced by striking objects outside of the body 79 



b. The music of flight 80 



