INSECTS : WINGS AND THEIE APPENDAGES. 



93 



A piece of one of the wing-cases of this beetle is 

 gummed to the slide now upon the stage. We look at 

 it by reflected light with a magnifying power of 130 



a black 



ground, 



on which are 



SCALES OF DIAMOND-BEETLE, 



diameters. We see 

 strewn a profusion 

 of what look like 

 precious stones blaz- 

 ing in the most gor- 

 geous lustre. To- 

 pazes, sapphires, 

 amethysts, rubies, 

 emeralds seem here 

 sown broadcast; and 

 yet not wholly with- 

 out 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 regu- 

 larly oval in form, for one end is rather more pointed 

 than the other ; there is no appearance of a footstalk, 

 and by what means they adhere, I know not ; they are 

 evidently attached in some manner by the smaller ex- 

 tremity to the velvety black surface of the wing-case. 

 The gorgeous colours 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 re- 

 flected. 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 colours are the chief reflected. Yet 



