INDEX 



473 



Tracheae. See Air-tubes. 

 Transformation, ii, i6o, 196, 331- 



^ - .336 



Triassic fossil insects, 339, 341 



Tribolium, 425 



Trichoptera, characters, 315 ; rela- 

 tionships, 335-336 ; geo- 

 logical history, 341-342 



Trilobites, 349 



Trochopus, 294 



Trophallaxis, 224-225, 243, 257- 

 . ^58 



Tropisms, 92-93, 95-100 



Trj-panosoma, 412, 429 



Tsetse-fly and cattle-disease, 410- 

 412 ; and sleeping-sickness, 



429-431 

 Tympanal organs, 80 

 Tyroglyphidae, nymphal mites 



carried by flies, 416-417 



Use-inheritance, 357-358, 361- 

 36s 



Vagina, 143 



Vanessa io, larval nests, 214 ; winter- 

 ing, 264, 299 ; variation, 



353-354 

 Variation, 121, 150-157 

 Vedalia cardinalis, 423 

 Velia currens, 282 

 Ventriculus. See Stomach. 

 Vermiform larva, 186 

 Vespa, societies and nests, 224-225, 



234-236 ; species, 321-323 

 Vision, 87-93 



WAiiULE-FLiEs, See Hypoderma. 



Warning colours, 371-374 



Wasps, larvae, 182 ; families, 215 ; 

 societies, 222-225, 234-236 ; 

 wintering, 299-300 ; classi- 

 fication, 320-323 ; catching 

 flies on cattle, 398 



White ants. See Termites. 



Wingless insects, 164, 307 



Wing-rudiments, external, 162-164 ; 

 internal, 173-174, 180 ; ab- 

 normal, 187-189, 190 



Wings, 3, 54-56 ; muscles of, 56- 

 57 ; coupling, 58-60 ; growth 

 of, 1 61-174 ; i" classifica- 

 tion, 307-309 ; evolutionary 

 modification, 330-33 1 ; origin, 

 345-346 



Wintering of insects, 298-304 



Wood-eating insects, 213, 219, 384 



Xenopsylla cheopsis'^and plague, 



437 

 Xestobium tesselatum, 427 



Yellow fever and mosquito, 434- 



435 

 Yolk, 10, 1 50-1 5 1 



Zygaena, larval changes, 303 

 Zygoptera, 313 

 i Zygote, 117, 120-121 



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