On the Variation of Species, with Especial Reference to the Insecta / Followed by an Inquiry into the Nature of Genera

INDEX.

• Aberration, perhaps indicated universally, 16, 17, 18.
• Aborigines, insect, unimportant for climatal modifications, 25, 26, 27.
• Acalles, the Canarian type of, apparent on the Salvages and Dezertas, 124.
• —— Neptunus, Woll., perhaps a state of A. argillosus, 124.
• Achatina Eulima, Lowe, its extinction in Porto Santo, 131.
• Achenium Hartungii, Heer, a form of A. depressum, 65.
• Acherontia Atropos, Linn., its introduction into Madeira perhaps recent, 74.
• Adimonia, the capture of, out at sea, 150.
• Aëpus marinus, Ström., pallid hue of, 64.
• —— Robinii, Lab., pallid hue of, 64.
• Agabus bipustulatus, Linn., unaffected by climate, 31.
• Alligators, their peculiarity to S. America, 143.
• Alpine species, some peculiarly so, 40.
• Altitude and latitude, sometimes reciprocal, 35, 114.
• Amyeterus, its concentration in Australia, 143.
• Amyot, M., his 'Méthode Mononomique,' 164.
• Analogies, Lord Bacon on the importance of, 13;
• why necessary to be studied, 14.
• Analogy, argument from, 10, 11, 12.
• Anchomenus marginatus, Linn., slightly modified in Madeira, 38.
• Andes, dissimilarity of the fauna on the opposite sides of the, 146.
• Anobium striatum, Oliv., unaffected by climate, 31.
• Antennæ, joints of, said occasionally to vary, 96.
• Anthicus bimaculatus, Illig., variability of, near the sea, 63.
• —— fenestratus, Schmidt, slightly modified in Madeira, 38.
• —— humilis, Germ., variability of in salt places, 63.
• —— instabilis, Hoffm., pallid hue of, 64.
• Anthonomus ater, Mshm, very small in Lundy Island, 58, 73.
• Aphelocheirus æstivalis, Fabr., the hemelytra of, sometimes fully developed, 100.
• Aphodius nitidulus, Fabr., paler in Madeira than in Europe generally, 65.
• Aphodius plagiatus, Linn., usually black in England, 61;
• two distinct states of, indicated, 105.
• Apocyrtus, its concentration in the Philippine Islands, 143.
• Apotomus, common to Madeira and Sicily, 139.
• Argutor, always apterous in Madeira, 82;
• trophi of, almost identical with those of Calathus, 175.
• Armadillos, their peculiarity to S. America, 143.
• Armitage, Mr., on Cicindela fasciatopunctata from Mount Olympus, 41.
• Arrangement, a lineal one is not indicated in Nature, 163.
• Atlantic continent, Prof. E. Forbes on the former existence of, 137.
• Atlantis of the ancients, the impossibility of its being identified with a former Atlantic region, 140;
• perhaps the New World, 141.
• Atlantis, the genus, a modification of Laparocerus, 143.
• Azores, the colonization of, by two Madeiran Helices, 133.
• Bacon, Lord, on the importance of analogies, 13;
• on the Atlantis of the ancients, 141;
• on the necessity of observation for forming science, 159.
• Banksias, their concentration in Australia, 142.
• Barriers, natural, the difference between primary and recent, 145;
• their hindrance to insect diffusion, 145.
• Bembidium Atlanticum, Woll., paler in Porto Santo than in Madeira, 66;
• the variations to which it is subject, 107, 108.
• —— bistriatum, Dufts., paler in saline districts, 62.
• —— ephippium, Mshm, pallid hue of, 64.
• —— obtusum, Sturm, varies in southern latitudes, 33.
• —— pallidipenne, Illig., pallid hue of, 64.
• —— saxatile, Gyll., variety of, on the south coast of England, 60.
• —— Schmidtii, Woll., perhaps a state of B. callosum, 66.
• —— scutellare, Germ., pallid hue of, 64.
• —— tabellatum, Woll., perhaps a state of B. tibiale, 66.
• Berginus, common to Madeira and Sicily, 139.
• Black Rat, nearly exterminated in England, 178.
• Blemus areolatus, Creutz., paler in brackish places, 62.
• Bolitochara assimilis, Kby, smallness of, in the Scilly Islands, 73.
• Boromorphus, common to Madeira and Sicily, 139.
• Brachinus crepitans, Linn., two distinct sizes of, frequently indicated, 105.
• Bradycellus fulvus, Mshm, apterous in Madeira, 85.
• Bread-fruit Trees, their peculiarity to the South Sea Islands, 142.
• Calathus, apterous in Madeira, 82; its trophi almost identical with those of Pristonychus, 175.
• —— complanatus, Koll., varies from altitude, 39;
• variety of, on one of the Madeira Islands, 88.
• —— fuscus, Fabr., slightly modified in Madeira, 38, 85.
• Calathus melanocephalus, Linn., smallness of, in the Scilly Islands, 73.
• —— mollis, Mshm, variable in its wings, 43;
• lurid colour of, 64.
• Calcareous soils, effect of, on the aspect of insects, 66.
• Calceolarias, their concentration on the Andes, 142.
• Calosoma, a species of, ten miles from shore, 147;
• the genus, mergescgradually into Carabus, 175.
• —— Syncophanta, Linn., its power of crossing the sea, 147.
• Canary Islands, migratory direction of their insect population, 119.
• Carabidæ, inconstant in their organs of flight, 43;
• family of, nearly similar throughout in its oral organs, 174.
• Carpophilus hemipterus, Linn., unaffected by climate, 31.
• Caulotrupis conicollis, Woll., large size of, on one of the Madeira Islands, 88, 109.
• —— lucifugus, Woll., varies from isolation, 90, 109.
• Causes, never final ones which we investigate, 191.
• Centrinus, its concentration in S. America, 143.
• Ceutorhynchus contractus, Mshm, smallness of, in Lundy Island, 59, 73.
• Cholovocera, common to Madeira and Sicily, 139.
• Choreius ineptus, Westw., on a winged state of, 44.
• Chorosoma miriforme, the development of the wings of, 100.
• Chrysomela, apterous in Madeira, 82.
• Chrysomelæ, vary from altitude, 41.
• Chrysomelidæ, almost absent in Tierra del Fuego, 47.
• Cicindela fasciatopunctata, Germ., a state of C. sylvatica 41.
• Cicindelidæ, often variable, 41.
• Cillenum laterale, Sam., lurid hue of, 64.
• Cimex apterus, Linn., the development of the wings of, 100.
• —— lectularius, Linn., on the development of the wings of, 45.
• Cistela sulphurea, Linn., its variability near the sea, 60.
• Clausilia deltostoma, Lowe, a Porto-Santan form of, 134.
• Climatal modifications significant, although small, 42.
• Climate, not important as a disturbing cause, 23, 24, 31, 32, 42.
• Clouded-yellow Butterfly, unaffected by climate, 31.
• Clypeaster pusillus, Gyll., differs slightly in Madeira, 65.
• Coast, inconstancy of insects in the vicinity of the, 57.
• Coccinella 7-punctata, Linn., unaffected by climate, 31.
• Colias Edusa, Fabr., unaffected by climate, 31.
• Colour, its inconstancy in insects found near the sea, 57, 58.
• —— of insects, affected by isolation, 88.
• Colymbetes, a species of, captured forty-five miles from shore, 149, 150.
• Compensation, generally apparent when an insect is deprived of an organ or sense, 81.
• Coranus subapterus, Curt., the development of the wings of, 101.
• Cordillera, Mr. Darwin on the fauna of the, 145.
• Corylophus, apterous in Madeira, 82.
• Criomorphus, Curtis, referable to the genus Delphax, 45.
• Cyclostoma lucidum, Lowe, its extinction in Porto Santo, 131.
• Cynthia Cardui, Linn., unaffected by climate, 32.
• Cynucus, a species of, seventeen miles from shore, 150.
• Cyrtonota, its concentration in S. America, 143.
• Darwin, Mr., on the fauna of the Galapagos, 23;
• relative proportions of the insect tribes in the tropics, 28, 29;
• on the insects of Tierra del Fuego, 47;
• on the natural features of Tierra del Fuego, 50;
• on the insects of Keeling Island, 55;
• on the insects of St. Helena, 55;
• on the insects of Ascension, 55;
• on the apterous condition of insular species, 86;
• on the fauna of the Cordillera, 145;
• on a Calosoma captured at sea, 147;
• on insects captured in the sea, 149, 150;
• on the disappearance of animals before more powerful ones than themselves, 178.
• Dawson, Rev. J. F., on a variety of Bembidium saxatile, 60.
• Definition of the term 'species,' 4;
• of the term 'variety,' 4.
• Delphax, on the development of the wings of, 45.
• Dermestes vulpinus, Fabr., unaffected by climate, 31.
• Deucalion, its occurrence on the Salvages and Dezertas, 125.
• —— Desertarum, Woll., its sedentary nature, 125, 126, 127.
• Dichelus, its concentration in S. Africa, 143.
• Differences, when to be regarded as specific, 6;
• too exclusively studied, 12.
• Diffusion, various means of, which operate on the insect tribes, 148.
• Disturbing agents, Prof. Henfrey on, 8.
• Ditylus, the same type of, indicated in the Canaries and Salvages, 124.
• Domesticated animals, pliable nature of, 187, 192.
• Dromius arenicola, Woll., representative of D. obscuroguttatus, 66.
• —— fasciatus, Gyll., its paleness near the sea, 63.
• —— negrita, Woll., perhaps an ultimate state of D. glabratus, 85.
• —— obscuroguttatus, Dufts., its changes in Madeira, 36, 37, 38;
• apterous in Madeira, 84.
• —— sigma, Rossi, its colour affected by isolation, 88, 89.
• Elevation, sometimes corresponds with latitude, 35, 114.
• Ellipsodes glabratus, Fabr., singular variety of, on one of the Madeira Islands, 88, 109.
• Elytra, connateness of, a variable character, 96.
• 'Endemic,' to what species the term is applicable, 118.
• Entomology, the study of, does not necessarily cramp the mind, 111.
• Ephistemus, apterous in Madeira, 82.
• Eucalypti, their concentration in Australia, 142.
• Eunectes sticticus, Linn., unaffected by climate, 31.
• Euphorbias, their concentration in Southern Africa, 142.
• Eurygnathus Latreillei, Lap., variety of, on one of the Madeira Islands, 88, 109.
• Exceptions, not be allowed to negative a law, 72, 73.
• Extinction of species, as indicated in the Madeiran Helices, 131;
• the only cause by which genera may be abruptly defined, 176.
• Forbes, Prof. E., on the origin of the British animals and plants, 130;
• his epochs of migration of the British animals and plants, 136;
• on the existence of a former Atlantic continent, 137.
• Forests, the hindrance which they offer to insect-diffusion, 154.
• "Fortunate Islands" of the ancients, probably the Canarian group, 141.
• Galapagos, fauna of, 23.
• Genera, the nature of, often misunderstood, 160;
• a familiar explanation of, 160, 161, 162;
• cannot be abrupt except from accident, 169;
• how to be defined, 169;
• the types of, usually situated towards the centres of the several groups, 170;
• the types of, usually evenly balanced in their structural characters, 171, 172;
• may be abruptly defined from accidental causes, 176, 177.
• Generic areas, an important feature throughout Nature, 130, 141, 184.
• Geology, a necessary item in the study of insect-diffusion, 113.
• Germanic plains, the, probably a primary area of diffusion, 130.
• Gerris, on the development of the wings of, 100.
• Gould, Mr., on the Swallows of Malta, 102.
• Gymnaëtron, blood-red dashes characteristic of, 62.
• —— Campanulæ, Linn., its smallness on the Cornish coast, 58.
• —— Veronicæ, Germ., a variety of G. niger, 62.
• Hadrus illotus, Woll., perhaps a form of H. cinerascens, 66.
• Haliplus obliquus, Gyll., dark state of, in Ireland, 67.
• Haltica exoleta, Fabr., its variability on the coast, 59.
• Harcourt, Mr., on the discovery of Madeira, 49, 50.
• Harpalus vividus, Dej., changes to which it is subject, 67, 68, 69;
• variable in the connateness of its elytra, 96, 97.
• Hegeter, its maximum attained in the Canaries, 120.
• —— elongatus, Oliv., its migration from the Canaries, 120;
• of a more adaptive nature than its allies, 121.
• —— latebricola, Woll., its occurrence in the Salvages, 120.
• Helices, have often two distinct states, 106;
• many of them representative in the Madeira Islands, 128, 129;
• those in the Madeiras chiefly of slow migratory powers, 130, 131.
• Helix attrita, Lowe, its local character, 132.
• —— Bowdichiana, Fér., perhaps a gigantic state of H. punctulata, 106.
• —— calculus, Lowe, sedentary nature of, 132.
• Helix commixta, Lowe, sedentary nature of, 132.
• —— coronata, Desh., its peculiarity to Porto Santo, 128;
• its occurrence beneath the surface of the ground, 131.
• —— coronula, Lowe, its peculiarity to the Southern Dezerta, 128.
• —— Delphinula, Lowe, the Madeiran representative of H. tectiformis in Porto Santo, 129.
• —— discina, Lowe, a form of H. polymorpha, 133.
• —— erubescens, Lowe, its powers of diffusion greater than those of its allies, 133;
• sensitive to external influences, 134.
• —— fluctuosa, Lowe, its extinction in Porto Santo, 131.
• —— hirsuta, Say, two distinct states of, 106.
• —— lapicida, Linn., its extinction in Porto Santo, 131.
• —— latens, Lowe, the Madeiran representative of H. obtecta in Porto Santo, 129.
• —— lincta, Lowe, the common Madeiran form of H. polymorpha, 134.
• —— Lowei, Pfr., perhaps a gigantic state of H. Portosanctana, 106.
• —— papilio, Lowe, a form of H. polymorpha, 133.
• —— paupercula, Lowe, its powers of diffusion greater than those of its allies, 133.
• —— polymorpha, Lowe, sensitive to external influences, and of great diffusive powers, 133.
• —— Portosanctana, Sow., its peculiarity to Porto Santo, 129.
• —— pulvinata, Lowe, a form of H. polymorpha, 133.
• —— saccharata, Lowe, a local state of H. polymorpha, 134.
• —— senilis, Lowe, the Dezertan form of H. polymorpha, 134.
• —— squalida, Lowe, the Madeiran representative of H. depauperata in Porto Santo, 129.
• —— tiarella, Webb, its sedentary nature, 128.
• —— undata, Lowe, its peculiarity to Madeira proper, 129.
• —— Vulcania, Lowe, its peculiarity to the Dezertas, 129.
• —— Wollastoni, Lowe, sedentary nature of, 132.
• Helobia nivalis, Payk., perhaps a state of H. brevicollis, 40.
• Helops, always apterous in Madeira, 82.
• —— confertus, Woll., varies from altitude, 39.
• —— futilis, Woll., varies from isolation, 109.
• —— testaceus, Küst., pallid hue of, 64.
• —— Vulcanus, Woll., large size of, on one of the Madeira Islands, 88.
• Henfrey, Prof., on disturbing agents, 8.
• Herschel, Sir John, on the requisites for an observer, 12.
• Hipparchia Semele, Linn., has a distinct aspect in Madeira, 34.
• Hipporhinus, its concentration in S. Africa, 143.
• Holme, Mr., on Olisthopus rotundatus in the Scilly Islands, 58, 102;
• on a winged state of Phosphuga atrata, 102.
• Holoparamecus, common to Madeira and Sicily, 139.
• —— Niger, Aubé, different in Madeira and Sicily, 33.
• Hooker, Dr., on the insects of Kerguelen's Land, 86.
• Humboldt, his notice of Sphinxes and flies high up on the Andes, 149.
• Humming-Birds, their peculiarity to S. America and the W. Indies, 142.
• Hydrobius, apterous in Madeira, 82;
• the capture of, out at sea, 150.
• Hydrometridæ, on the development of the wings of, 100.
• Hydroporus, the capture of, out at sea, 150.
• —— confluens, Fabr., unaffected by climate, 31.
• Hypsonotus, its concentration in S. America, 143.
• Influence of climate not important, 23.
• Insect-aberration, perhaps a universal fact, 16, 17, 18.
• Insulæ Fortunatæ of Juba, probably the Canarian Group, 141.
• Ireland, poverty of the fauna of, 52, 53;
• the south-west of, has something in common with Madeira, 139.
• Islands, faunas of, often too greatly magnified, 70;
• the species of, generally more isolated in their structure than those of continents, 177.
• Isolation, effects of, on insect-stature, 71.
• Ixias, their concentration in Southern Africa, 142.
• Kangaroos, their concentration in Australia, 142.
• Kerguelen's Land, insects of, 86.
• Kirby, Rev. W., on insects washed up on the Suffolk coast, 147.
• Læmophlœus pusillus, Schönh., unaffected by climate, 31.
• Lamprias chlorocephalus, Ent. H., two distinct sizes of, frequently indicated, 105.
• Laparocerus morio, Schönh., large size of, on one of the Madeira Islands, 88.
• Latitude and altitude, sometimes reciprocal, 35.
• Leistus montanus, Steph., has been supposed to be equal to L. fulvibarbis, 40.
• Lemur, its peculiarity to Madagascar, 143.
• Litargus, common to Madeira and Sicily, 139.
• Lixus angustatus, Fabr., unaffected by climate, 31.
• Localities, some naturally more productive than others, 53, 54.
• Longitarsus, the native species of, apterous in Madeira, 82.
• Loricera, apterous in Madeira, 82.
• Lowe, Rev. R. T., his capture of the Deucalion Desertarum, 127.
• Lundy Island, smallness of the insects in, 58, 59;
• occurrence of the Black Rat in, 178.
• Lycæna Phlœas, Linn., darker in Madeira than in England, 34.
• Lyell, Sir Charles, on Helix hirsuta, 106;
• on the fossil period of the Madeiran Helices, 129;
• on insects washed up on the shore, 148;
• on the effect of gales in the transportation of insects, 148;
• on the effects of a volcanic eruption in destroying species, 179;
• on the flexible nature of certain animals and plants, 187;
• on the greater differences which varieties often present than do species, 193.
• Lygæus brevipennis, Latr., on the development of the wings of, 101.
• Macronota, its peculiarity to Java, 143.
• Madeira, has some features in common with Tierra del Fuego, 48, 49, 50, 51;
• former state of, 48, 49;
• great fire on the southern side of, 49;
• origin of the name of, 50; the insects of, 55;
• the tendency of its insects to become apterous, 82;
• the migratory direction of its insect population, 119;
• the local nature of its various species, 152, 153.
• Magnolias, their concentration in Central America, 142.
• Malta, Mr. Gould on the birds of, 102.
• Malthodes Kiesenwetteri, Woll., perhaps a state of M. brevicollis, 66.
• Man, agency of, in the destruction of species, 179.
• Mantura Chrysanthemi, Ent. H., variability of, in Lundy Island, 59.
• Marsupialia, their concentration in Australia, 142.
• Mesembryanthemums, their concentration in Southern Africa, 142.
• Mesites, a modification of Cossonus, 144.
• —— Maderensis, Woll., its near relationship to the M. Tardii, 141.
• —— Tardii, Curtis, its variability near the coast, 58.
• 'Méthode Mononomique,' the unsoundness of, 164-168.
• Migratory powers, slowness of, in the Madeiran Helices, 130-132.
• —— progress, direction of, in the Madeiran animals, 120, 135.
• Mimosas, their concentration in Australia, 142.
• Mollusca, Terrestrial, often present two distinct states, 106.
• Moluris, its concentration in S. Africa, 143.
• Monochelus, its concentration in S. Africa, 143.
• Mountain-chains, their hindrance to insect-diffusion, 145.
• Mountain-tops, either very prolific in insect life, or else barren, 115.
• Mus Rattus, almost exterminated in England, 178.
• Mycetoporus pronus, Erichs., two distinct states of, indicated, 106.
• Myrtles, their concentration in Australia, 142.
• Naturalist, the, what his province to investigate, 158.
• Nature, not irregular because presenting occasional anomalies, 94.
• Naupactus, its concentration in S. America, 143.
• Nebria complanata, Linn., unusually pale near Bordeaux, 33;
• pallid hue of, 64.
• New World, some of its insects perhaps but states of those of the Old, 37.
• Nomenclature, a binomial system the only true one, 164, 168.
• Notaphus, the capture of, out at sea, 150.
• Notiophili, extremely variable, 40.
• Notiophilus geminatus, Dej., large size of, on one of the Madeira Islands, 88.
• Observation, indispensable in natural science, 20, 159, 192.
• Ocean, the, its hindrance to insect-diffusion, 145.
• Ochthebius marinus, Payk., lurid hue of, 64.
• Olisthopus, apterous in Madeira, 82.
• —— Maderensis, Woll., large state of, on one of the Madeira Islands, 88, 89.
• —— rotundatus, Payk., very small in the Scilly Islands, 58, 73;
• subapterous in the Scilly Islands, 102.
• Omaseus nigerrimus, Dej., a form of O. aterrimus, 33.
• Omias Waterhousei, Woll., large state of, on one of the Madeira Islands, 88, 109.
• Oncocephalus griseus, development of the wings of, 101.
• Othius, apterous in Madeira, 82.
• Ourangs, their peculiarity to the Indian Islands, 143.
• Oxyomus, a modification of Aphodius, 144.
• Pachymerus brevipennis, the development of the wings of, 100.
• Pachyrhynchus, its concentration in the Philippine islands, 143.
• Painted-Lady Butterfly, unaffected by climate, 32.
• Papilio Machaon, Linn., unaffected by climate, 31.
• Paropsis, its concentration in Australia, 143.
• Patagonia, insects of, distinct from those of Tierra del Fuego, 47, 48.
• Patrobus septentrionis, Dej., has been supposed to be a state of P. excavatus, 40.
• Pecteropus, its maximum attained in the Canaries, 124.
• —— Maderensis, Woll., varies from altitude, 39.
• —— rostratus, Woll., varies from isolation, 90.
• Pelargoniums, their concentration in Southern Africa, 142.
• Pelophila borealis, Payk., larger in Ireland than in the Orkneys, 33.
• Phaleria cadaverina, Fabr., pallid hue of, 64.
• Philhydrus melanocephalus, Oliv., two states of, frequently indicated, 105.
• Phlæophagus, apterous in Madeira, 82.
• Phosphuga atrata, Linn., taken with the wings developed, 102.
• —— subrotundata, Leach, the Irish form of the P. atrata, 33.
• Phytophaga, preponderance of, in the tropics, 28, 29.
• Pieris Brassicæ, Linn., varies in Nepaul and Japan, 34.
• Pissodes notatus, Fabr., unaffected by climate, 30.
• Platyomus, its concentration in S. America, 143.
• Platyrrhini, their peculiarity to S. America, 143.
• Pogonus luridipennis, Germ., lurid hue of, 64.
• Pontia Brassicæ, Linn., its introduction into Madeira probably recent, 74.
• Porto Santo, origin of the name of, 49;
• a generic area of radiation for certain Helices, 130.
• Predacious insects, less numerous in the tropics, 28, 29.
• Prostemma guttula, Fabr., the development of the wings of, 100, 101.
• Psylliodes, a variable species of, in Lundy Island, 60.
• —— erythrocephala, Linn., two distinct states of, frequently indicated, 105.
• —— marcida, Illig., pallid hue of, 64.
• —— nigricollis, Mshm, a pale state of the P. erythrocephala, 105.
• —— vehemens, Woll., varies from isolation, 90.
• Pterostichus, its various divisions are natural ones, 175.
• Ptini, their stature affected by isolation, 74;
• which characters of, are the most constant, 104.
• Ptinus albopictus, Woll., its changes on the islands of the Madeiran Group, 75-77.
• Pupa, often two distinct states of, 106.
• Purpurariæ of the ancients, probably the Madeiran Group, 141.
• Pyrenean region, the, perhaps a primary area of diffusion, 130.
• Reasoning, not sufficient of itself for the formation of science, 159.
• Red-Admiral Butterfly, its introduction into Madeira perhaps recent, 74.
• Reduviadæ, on the development of the wings of a representative of the, 101.
• Representative species, exemplified by the Madeiran Helices, 128, 129, 185;
• where frequently to be recognized, 183.
• Rhyzopertha pusilla, Fabr., unaffected by climate, 31.
• Rivers, their power of transporting insects along their course, 149.
• Saline spots, variation of insects in, 57.
• Salvages, occurrence of a Canarian form on the, 120, 124.
• Saprinus, a modification of Hister proper, 143.
• —— nitidulus, Fabr., two distinct states of, indicated, 106.
• Scarabæus, the capture of, out at sea, 150.
• Scarites abbreviatus, Koll., large size of, on one of the Madeira Islands, 88;
• varies both from isolation and altitude, 91.
• Sciences, the, should assist rather than oppose each other, 155, 156.
• Scydmænus Helferi, Schaum, smaller in Madeira than in Sicily, 65.
• Scymnus, an apterous species of, in Porto Santo, 82.
• Sea, inconstancy of insects in the vicinity of the, 57.
• Sicily, the fauna of, has much in common with that of Madeira, 139.
• Silpha atrata, Linn., presents a distinct state in Ireland, 33.
• Silybum Marianum, Grtn., its stalks the food of a Ptinus, 76.
• Similitudes, Lord Bacon on the importance of, 13.
• Sitonia gressoria, Illig., perhaps a form of the S. grisea, 33.
• Sitophilus granarius, Linn., unaffected by climate, 31.
• Sitophilus oryzæ, Linn., unaffected by climate, 31.
• Sloths, their peculiarity to S. America, 143.
• Species, definition of the term, 4;
• familiar explanation concerning the nature of, 161, 162;
• limitation of, how to be attempted, 192;
• limits of, real, though often difficult to trace out, 193;
• in a certain sense both unstable and permanent, 194.
• Specific centres of creation, 5.
• Sphinx Convolvuli, Linn., its introduction into Madeira probably recent, 74.
• Spinola, on one of the Reduviadæ, 101;
• on Oncocephalus griseus, 101.
• Stapelias, their concentration in Southern Africa, 142.
• States, large and small ones indicated in some insects, 105.
• Stature of insects, smaller in islands than on continents, 70.
• Stenolophus Skrimshiranus, Steph., perhaps a state of S. Teutonus, 63.
• Stenus Heeri, Woll., two distinct states of, indicated, 106.
• Structural characters, seldom variable in the Insecta, 95.
• Subsidences, the effect of, on insect life, 114.
• Swallow-Tail Butterfly, unaffected by climate, 31.
• Syncalypta, apterous in Madeira, 82.
• Tachyporus nitidicollis, Steph., perhaps a state of T. obtusus, 33.
• Tarphii, their economy in the Madeira Group, 121.
• Tarphius, its maximum attained in Madeira proper, 121;
• common to Madeira and Sicily, 139.
• —— gibbulus, Germ., the Sicilian exponent of the genus, 123.
• —— Lowei, Woll., of a more adaptive nature than its allies, 122.
• Tarus, always apterous in Madeira, 82.
• —— lineatus, Schönh., assumes a distinct state in Madeira, 65.
• Telephorus testaceus, Linn., its variability in Lundy Island, 59.
• Thompson, Mr., on the reptiles of Ireland, England, and Belgium, 136.
• Thorictus, common to Madeira and Sicily, 139.
• Tierra del Fuego, insects of, 47;
• has many characters in common with Madeira, 48-51.
• Time, an important item in the question of modifications, 77.
• Toucans, their peculiarity to S. America and the W. Indies, 142.
• Transmutation-theory, unsoundness of the, 186-189;
• how it took its rise, 190.
• Trechus, always apterous in Madeira, 82.
• —— alticola, Woll., perhaps a state of T. custos, 39.
• —— lapidosus, Daws., pallid hue of, 64.
• Tree-Porcupines, their peculiarity to S. America, 143.
• Tribolium ferrugineum, Fabr., unaffected by climate, 31.
• Trogosita mauritanica, Linn., unaffected by climate, 31.
• Tropics, exuberance of the, 27, 28;>
• relative proportions of the insect tribes within the, 28, 29.
• Tychius, always apterous in Madeira, 82.
• Unity, indicated in the organic creation, 179, 180.
• Vanessa Atalanta, Linn., has a different aspect in N. America, 34;
• perhaps a recent introduction into Madeira, 74.
• —— Callirhoë, Fabr., smaller in Porto Santo than in Madeira, 73.
• Variation in the Insecta, a matter of experience, 7, 8, 15;
• probable from analogy, 15;
• perhaps indicated in every individual, 16, 17, 18;
• restricted, 35.
• Variety, definition of the term, 4.
• Velia, on the development of the wings of, 100.
• Waterhouse, Mr., his opinion concerning generic types, 172.
• Westwood, Mr., on Papilio Machaon from the Himalayas, 32;
• on American specimens of Lycæna Phlœas, 34;
• on the effect of heat in developing the wings of insects, 44;
• on a winged state of Choreius ineptus, 44;
• on the development of the wings in Delphax, 45;
• on a winged state of Cimex lectularius, 45;
• on Aphelocheirus æstivalis, 100;
• on the development of the wings of the Hydrometridæ, 100;
• on Cimex apterus, 100;
• on Prostemma guttala and Coranus subapteras, 101;
• on the development of the wings of Lygæus brevipennis, 101.
• Whewell, Dr., on the natural causes which science has to investigate, 191.
• White-Cabbage Butterfly, varies in Nepaul and Japan, 34.
• Winds, the effects of, in the diffusion of insects, 148.
• Wings of insects, subject to undue development in hot seasons, 43;
• liable to become gradually obsolete in islands, 81;
• more variable than other organs, 97.
• Xenostrongylus, its geographical distribution, 124;
• common to Madeira and Sicily, 139.
• Zargus pellucidus, Woll., variety of, on one of the Madeira Islands, 88.