210 INSECTS ABIJOAO. 



elytra, those organs are seen to Le thickly covered with a pro- 

 fusion of glittering scales, set closely together like those of a 

 golden carp. Their general effect is emerald green, with a little 

 dash of pink and gold; but the best plan is, to take one scale 

 and analyse its colours. Each scale will then be seen to consist 

 of a number of colours, such as yellow, pink, blue, and green, 

 the last hue being generally the most brilliant. Every one of 

 the scales has one portion which is more brightly illuminated 

 than the others, and the colour of this spot changes together 

 with the direction of the light, casting successively every hue of 

 the rainbow. 



Should the observer merely look down upon the scales, he 

 will see the general effect of this varied colouring; but if he turns 

 the Beetle so as to get a side view of the scales, he will perceive 

 how that effect is produced. Each scale is covered with a 

 number of very fine parallel ridges, or striae, the effect of which 



X"^*^ 



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Fio. lOo— Cyplius gloriaudus. 

 (Gold-green, with black marks.) 



IS to break up the light that produces those wonderful opalescent 

 effects which have been described. Indeed, the opal owes its 

 well-known changnig tints to a similar cause, the stone having 

 multitudes of the minutest imaginable fractures which produce 

 exactly the same effect as the striae of the scales. Glass which 

 has been buried for a very long time becomes opalescent from 

 the same cause, as everyone knows who has seen the glass 

 vessels that have been taken out of Egyptian tombs and other 

 sepulchres of ancient date. 



The head, thorax, legs, and under surfaces are equally covered 

 with these scales, which in some places take a reddish hue 

 as their ground colour. On the thorax thev seem to be rather 



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