_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.
_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.