INSECTS: WINGS AND THEIR APPENDAGES 101 



fusion of what look like precious stones blazing in the 

 most gorgeous lustre. Topazes, sapphires, amethysts, ru- 

 bies, emeralds seem here sown broadcast; and yet not 

 wholly without regularity, for there are broad bands of 

 the deep black surface, where there are no gems, and, 

 though at considerable diversity of angle, they do all point 

 with more or less precision in one direction, viz., that of 

 the bands. 



These gems are flat transparent scales, very regularly 

 oval in form, for one end is rather more pointed than the 

 other; there is no appearance of a foot-stalk, and by what 

 means they adhere, I know not; they are evidently at- 

 tached in some manner by the smaller extremity to the 

 velvety black surface of the wing-case. The gorgeous ool- 

 ors seem dependent in some measure on the reflection of 

 light from their polished surface, and to vary according 

 to the angle at which it is reflected. Green, yellow, and 

 orange hues predominate; crimson, violet, and blue are 

 rare, except upon the long and narrow scales that border 

 the suture of the wing-cases, where these colors are the 

 chief reflected. Yet there appears to be some positive 

 color in their substance; for in these latter scales, which 

 projecting beyond the edge of the wing-case can be exam- 

 ined as transparent objects, and that with a high power, 

 the transmitted light is richly colored with the same tints 

 as the same scales displayed under the Lieberkuhn. 



We may derive pleasant instruction from continuing 

 our observations on a few other wings of insects. If you 

 have ever thought on the subject, you have probably taken 

 for granted that the various sounds produced by insects 

 are voices uttered by their mouths. But it is not so. No 

 insect has anything approaching to a voice. Yocal sounds 



