xvi TABLE OF CONTENTS 



13. THE ORGANS OF HEARING 145 



a. The general features 145 



The tympana 145 



The chordotonal organs 145 



The scolopale and the scolopophore 146 



The integumental and the subintegumental scolopophores 146 



The structure of a scolopophore 146 



The structure of a scolopale 1 47 



The simpler forms of chordotonal organs 1 47 



The chordotonal ligament 147 



b. The chordotonal organs of larvae 148 



c. The chordotonal organs of the Acridiidae 148 



d. The chordotonal organs of the Locustidas and of the Gryllidae 1 49 



The trachea of the leg 150 



The spaces of the leg 151 



The supra-tympanal or subgenual organ 151 



The intermediate organ 1 5 2 



Siebold's organ or the crista acustica I5 2 



e. Johnston's organ I5 2 



14. SENSE-ORGANS OF UNKNOWN FUNCTIONS 



The sense-domes or the olfactory pores 1 54 



15. THE REPRODUCTIVE ORGANS 



a. The general features 156 



Secondary sexual characters 157 



b. The reproductive organs of the female 157 



The general features of the ovary 157 



The wall of an ovarian tube 158 



The zones of an ovarian tube 158 



The contents of an ovarian tube 158 



The egg-follicles 158 



The functions of the follicular epithelium 1 59 



The ligament of the ovary 1 59 



The oviduct 159 



The egg--calyx 159 



The vagina 159 



The spermatheca !59 



The bursa copulatrix 159 



The colleterial glands 160 



c. The reproductive organs of the male ' (l 



The general features of the testes i ( )O 



The structure of a testicular follicle 161 



The spermatophores 



Other structures . . 



