THE COLORS OF ANIMALS AND PLANTS. 



525 



can be equaled, by any productions of the trop- 

 ics. 1 But we may go further, and say that the 

 hardy plants of our cold temperate zone equal, if 

 they do not surpass, the productions of the 

 tropics. Let us only remember such gorgeous 

 tribes of flowers as the roses, peonies, holly- 

 hocks, and antirrhinums ; the laburnum, Wis- 

 taria, and lilac ; the lilies, irises, and tulips ; the 

 hyacinths, anemones, gentians, and poppies, and 

 even our humble gorse, broom, and heather; 

 and we may defy any tropical country to produce 

 masses of floral color in greater abundance and 

 variety. It may be true that individual tropical 

 shrubs and flowers do surpass everything in the 

 rest of the world, but that is to be expected, be- 

 cause the tropical zone comprises a much greater 

 land-area than the two temperate zones, while, 

 owing to its more favorable climate, it produces 

 a still larger proportion of species of plants, and 

 a great number of peculiar natural orders. 



Direct observation in tropical forests, plains, 

 and mountains, fully supports this view. Occa- 

 sionally we are startled by some gorgeous mass of 

 color, but as a rule we gaze upon an endless ex- 

 panse of green foliage, only here and there enli- 

 vened by not very conspicuous flowers. Even the 

 orchids, whose gorgeous blossoms adorn our 

 stoves, form no exception to this rule. It is only in 

 favored spots that we find them in abundance ; the 

 species with small and inconspicuous flowers great- 

 ly preponderate ; and the flowering season of each 

 kind being of short duration, they rarely produce 

 any marked effect of color amid the vast masses of 



1 It may be objected that most of the plants named are 

 choice cultivated varieties, far surpassing in color the 

 original stock, while the tropical plants are mostly unva- 

 ried wild species. But this does not really much affect 

 the question at issue. For our florists' gorgeous varieties 

 have all been produced under the influence of our cloudy 

 skies, and with even a still further deficiency of light, 

 owing to the necessity of protecting them under glass 

 from our sudden changes of temperature; so that they 

 are themselves an additional proof that tropical light and 

 heat are not needed for the production of intense and 

 varied color. Another impoitant consideration is, that 

 these cultivated varieties in many cases displace a num- 

 ber of wild species which are hardly, if at all. cultivated. 

 Thus there are scores of species of wild hollyhocks vary- 

 ing in color almost as much as the cultivated varieties, and 

 the same may be said of the pentstemons. rhododendrons, 

 and many other flowers ; and if these were all brought 

 together in well-grown specimens they would produce a 

 grand effect. But it is far easier, and more profitable, for 

 our nurserymen to grow varieties of one or two species, 

 which all require a very similar culture, rather than fifty 

 distinct specie% most of which would require special treat- 

 ment; the result being that the varied beauty of the tem- 

 perate flora is even now hardly known, except to botanists 

 and to a few amateurs. 



foliage which surround them. An experienced col- 

 lector in the Eastern tropics once told me that, al- 

 though a single mountain in Java had produced 

 three hundred species of Orchidese, only about two 

 per cent, of the whole were sufficiently ornamental 

 or showy to be worth sending home as a commer- 

 cial speculation. The Alpine meadows and rock- 

 slopes, the open plains of the Cape of Good Hope 

 or of Australia, and the flower-prairies of North 

 America, offer an amount and variety of floral color 

 which can certainly not be surpassed, even if it 

 can be equaled, between the tropics. 



It appears, therefore, that we may dismiss the 

 theory that the development of color in Nature 

 is directly dependent on, and in any way propor- 

 tioned to, the amount of solar heat and light, as 

 entirely unsupported by facts. Strange to say, 

 however, there are some rare and little-known 

 phenomena which prove that, in exceptional cases, 

 light does directly affect the colors of natural ob- 

 jects, and it will be as well to consider these be- 

 fore passing on to other matters. 



A few years ago Mr. T. W. "Wood called at- 

 tention to the curious changes in the color of the 

 chrysalis of the small cabbage-butterfly (Pontia 

 rapce) when the caterpillars were confined in 

 boxes lined with different tints. Thus in black 

 boxes they were very dark, in white boxes nearly 

 white ; and he further showed that similar changes 

 occurred in a state of nature, chrysalises fixed 

 against a whitewashed wall being nearly white, 

 against a red-brick wall reddish, against a pitched 

 paling nearly black. It has also been observed 

 that the cocoon of the emperor-moth is either 

 white or brown, according to the surrounding 

 colors. But the most extraordinary example of 

 this kind of change is that furnished by the chrys- 

 alis of an African butterfly (Papilio Nireus), ob- 

 served at the Cape by Mrs. Barber, and described 

 (with a colored plate) in the " Transactions of the 

 Entomological Society," 18T4, page 519. The cat- 

 erpillar feeds on the orange-tree, and also on a 

 forest-tree ( Vepris lanccolata) which has a lighter 

 green leaf, and its color corresponds with that of 

 the leaves it feeds upon, being of a darker green 

 when it feeds on the orange. The chrysalis is 

 usually found suspended among the leafy twigs 

 of its food-plant, or of some neighboring tree ; 

 but it is probably often attached to larger 

 branches, and Mrs. Barber has discovered that it 

 has the property of acquiring the color, more or 

 less accurately, of any natural object it may be in 

 contact with. A number of the caterpillars were 

 placed in a case with a glass cover, one side of 



