Page:Popular Science Monthly Volume 53.djvu/681

Rh  of parasitic insects, as undoubtedly the somewhat ponderous houses of the larvæ render them to a high degree impervious to the onslaughts of insect enemies; the cause of death must be looked for elsewhere. Death usually occurs after the larva has undergone metamorphosis, the pupa gradually shriveling up after assuming its proper form, nor can anything be done, apparently, to avert the calamity.

To return to the case moth's metamorphoses. The female insect, as we have seen, unlike the male, is destined never to desert the larval home. For her no hour of emergence ever comes. When the pupa has slept the appointed time, the unwieldy and almost motionless moth feels little of the movement of oncoming life then experienced by her lithe and lively partner; the animal, still resident within the habitaculum formed by the larva, splits asunder the pupa skin, and her transformations are complete; in some, at least, of the species the female imago is continually inclosed in the pupa case. Here, therefore, we have an insect which in its adult state is forever excluded from the light, and never even beholds its mate.

Having filled the bottom of their puparium with their ova, packed in the down rubbed from their own body, these females do not long survive. The moth is then literally nothing but thin skin. Reduced to a shriveled, dried, and scarcely animated morsel of this matter, she either presses herself through the opening of the case or, exhausted, the last feeble flicker of life burned out, expires within.



OTHING illustrates more vividly the change which has taken place during the present century in the attitude of naturalists toward the objects of their study than the colors of plants and animals. To the dried-specimen systematist of a hundred years ago color was an immutable factor in Nature. The delicate beauty of the butterfly, the iridescent hues of the paradise bird, the tawny stripes of the tiger, the somber shades of the reptile, the whiteness of the lily and the redness of the rose—these and the myriad other color phases in the living world were believed to exist now as the Creator designed them a few thousand years ago. To the naturalist they were chiefly valuable in enabling him to separate species from species in dreary Latin tomes. To the theologian they served to show the goodness of God in adorning man's passing abode. To the artist beauty was its own excuse for being.

But there were not wanting interpreters of Nature who saw that