Structure of the taste organs 282 Distribution in different orders of insects 282 Experimental proof 286 _d._ The organs of hearing 287 The ears or tympanal and chordotonal sense-organs of Orthoptera and other insects 288 Antennal auditory hairs 292 Special sense-organs in the wings and halteres 293 _e._ The sounds of insects 293 THE DIGESTIVE CANAL AND ITS APPENDAGES 297 _a._ The digestive canal 302 The œsophagus 303 The crop or ingluvies 303 The “sucking stomach” or food-reservoir 305 The fore-stomach or proventriculus 306 The œsophageal valve 311 Proventricular valvule 313 The peritrophic membrane 313 The mid-intestine 314 Histology of the mid-intestine 316 The hind-intestine 316 Large intestine 316 The ileum 317 The gastro-ileal folds 317 The colon 317 The rectum 318 The vent (anus) 319 Histology of the digestive canal 320 _b._ Digestion in insects 324 The mechanism of secretion 326 Absorbent cells 328 THE GLANDULAR AND EXCRETORY APPENDAGES OF THE DIGESTIVE CANAL 331 _a._ The salivary glands 331 _b._ The silk or spinning glands, and the spinning apparatus 339 The process of spinning 340 How the thread is drawn out 343 Appendages of the silk-gland (Filippi’s glands) 345 _c._ The cæcal appendages 347 _d._ The excretory system (urinary or Malpighian tubes) 348 Primitive number of tubes 353