[ GENERAL INDEX. 



Page Sec. 



Arrangement of the wings of insects 304 . 793 



Texture of the wings of insects ft 305 . 797 



Organization of the external skeleton 306 . 801 



Anatomy of the wings of insects ..,,,,.. . . . 306 . 802 



Appendages to external skeleton .... 307 . 804 



Spines 307 . 805 



Hairs 307 . 806 



Scales of Lepidoptera 307 . 807 



Muscular system of insects 308 . 808 



Muscles of the leg of Melolontha vulgaris 309 . 815 



Food of insects 310 . 817 



Structure of the mouth of insects 311 . 818 



Digestive system of insects 316 . 831 



Structure of alimentary canal 317 . 832 



Crop or "sucking-stomach" 317 . 833 



Gizzard 318 . 834 



Stomach proper 318 . 835 



Small intestine 318 . 836 



Colon 318 . 836 



Salivary vessels 319 . 838 



Hepatic vessels 319 . 840 



Anal vessels 319 . 841 



Absorption of nutriment 320 . 842 



Respiratory system of insects 320 . 843 



Structure of tracheae 322 . 844 



Mechanism of respiration 324 . 848 



Circulatory system of insects 324 . 849 



Structure of the dorsal vessel or heart 325 . 850 



Diffused character of the circulation 326 . 853 



Structure of secerning vessels ....... 326 . 854 



Nervous system of insects 327 . 855 



Brain or encephalic ganglion, and nerves derived therefrom . . 327 . 856 



Ventral chain of ganglia . 327 . 857 



Motor and sensitive tracts 328 . 858 



Nervus vagus or recurrent nerve 329 . 859 



Sympathetic or splanchnic system 330 . 860 



On the senses of insects 330 . 861 



Sense of touch 330 . 862 



taste 331 . 863 



smell 331 . 864 



Hearing of insects 331 . 865 



Eyes of insects, of two kinds 332 . 867 



Structure of simple eyes 332 . 870 



compound eyes 332 . 871 



Inquiry concerning vision with compound eyes 334 . 874 



Sexes of the insect races distinct 335 . 875 



Structure and arrangement of male organs in Melolontha vulgaris 335 . 876 



Varieties observable in other insects 336 . 879 



Female generative system of Melolontha 336 . 880 



Formation of the eggs in the ovaria 337 . 883 



Appendages to oviduct 338 . 884 



Gluten-secretors 338 . 885 



Spermatheca 338 . 886 



Physiological use of spermatheca 338 . 887 



Generative apparatus of Meloe variegatus 339 . 889 



Structure of ovipositor 339 . 890 



of Sires 339 . 891 



Tenthredo 339 . 891 



Number of eggs laid by insects 340 . 892 



Fecundity of Aphides 341 . 894 



Impregnation of several successive generations by a single coitus . 341 . 894 

 This mode of reproduction referable to the nursing system of 



Steenstrup ..... .. .. . . . .. . -.<.;'* X. . 341 . 895 



