File:Animal and vegetable physiology, considered with reference to natural theology (1836) (14741752326).jpg

Identifier: animalvegetable01roge (find matches)
Title: Animal and vegetable physiology, considered with reference to natural theology
Year: 1836 (1830s)
Authors: Roget, Peter Mark, 1779-1869
Subjects: Biology Physiology Plant physiology Natural theology
Publisher: Philadelphia, Carey, Lea & Blanchard
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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ave observed in several detached scales that the colours theyexhibit by transmitted light are the complementary coloursto those which they display when seen by reflected liglit- The forms of these scales arc exceedingly diversified, notonly in different species, but also in different parts of thewings and body of the same insect; for the surface of thebody, generally, as well as the limbs, and even in some spe-cies the antennae are more or less covered with these scales.* • In the posthumous work of Lyonet, which lias lately appeared, nearly thewhole of six quarto plates are crowded with the delineations of tlic dillcrentforms of the scales found in the Bomhyx Cossus. Vol. I. 32 250 THE MECHANICAL FUNCTIONS. Fig. 164 exhibits some of the more usual shapes as they ap-pear when viewed with high magnifying powers. Each scale is inserted into the membrane of the wing bya short pedicle, or root, and overlaps the adjoining scales:and the wliole are disposed in rows with more or less regu-
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^ V ^ larlty; one row covering the next, like tiles on the roof of ahouse.* This imbricated arrangement, together with themarks that are left on the membrane of the wing where thescales have been rubbed off, are shown in Fig. 165, whichis a faithful delineation of the appearance of the wing of theHesperia Sloanus, seen through a powerful microscope.The membrane of the wing itself, when stripped of itsscales, is as perfectly transparent as that of the bee, and is,in like manner, supported by diverging nervures. Manybutterflies exhibit in some parts of the wing smooth pearlyspots, called by entomologists, ocelli, or eyes, which arisefrom those parts being naturally destitute of scales. Thenumber of these scales necessary to cover the surface of thewings must, from their minuteness, be exceedingly great.The moth of the silk worm (Bornbyx mori, Fig. 148,) * The scales on the wing of the Leplsma are of two kinds; one set beingarranged in rows, as usual, and the otliers, which are of a diff

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