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 ^5 



The integumental and the subintegumental scolopophores 146 



The structure of a scolopophore 146 



The structure of a scolopale 147 



The simpler forms of chordotonal organs 147 



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 Locustidae and of the Gryllidse 149 



The trachea of the leg 1 50 



The spaces of the leg . . . .. 151 



The supra-tympanal or subgenual organ 151 



The intermediate organ 1 52 



Siebold's organ or the crista acustica 152 



e. Johnston's organ 152 



14. SENSE-ORGANS OF UNKNOWN FUNCTIONS 



The sense-domes or the olfactory pores 154 



I 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 1 57 



The wall of an ovarian tube 158 



The zones of an ovarian tube 158 



The contents of an ovarian tube 1 58 



The egg-follicles 158 



The functions of the follicular epithelium 159 



The ligament of the ovary '. 159 



Thfr oviduct 159 



The egg-calyx 159 



The vagina 159 



The spermatheca 159 



The bursa copulatrix . .- 159 



The colleterial glands 160 



c. The reproductive organs of the male 160 



The general features of the testes 160 



The structure of a testicular follicle 161 



The spermatophores 162 



Other structures. . ..-.., 162 



