82 EVENINGS AT THE MICROSCOPE. 



we are considering is from the white portion of the wing 

 of Pieris Glaucippe, sl fine butterfly from China ; but a 

 similar structure is found in our own Garden Whites and 

 Meadow Browns (Piericlce and Satyridw). 



Scales taken from the brilliant changeable blue-o-reen 

 patch in the hind-wing of Papilio Paris, a fine Indian but- 

 terfly, have an interesting appearance. They are simply 

 pear-shaped in outline, with few longitudinal ribs set far 

 apart, and numerous strongly marked corrugations running 

 across between them. That these are really elevations of the 

 surface, is well seen in some scales, even with transmitted 

 light, and a high power; for the slopes of the wrinkles 

 that face the light display the lustrous emerald reflection 

 proper to the wing, while the transmitted colour of the 

 whole scale is a rich transparent red. 



The dimensions of the scales do not bear any certain 

 proportion to the size of the insect which is clothed with 

 them ; those from the broad wings of the noble Satnrnia 

 Atlas, for example, eight or nine inches in expanse, being 

 exceeded in size by some from those of our little native 

 Muslin Moth, an inch wide. 



You will say that what I am about to show you is a 

 lovely object ; but for its right display I must use a low 

 magnifying power, — not higher than a hundred diameters, 

 — with condensed light falling upon the surface. It is a 

 small fragment cut from the wing of Papilio Paris, show- 

 ing several rows of the scales in their natural arrangement. 

 The gem-like radiance of the glittering green scales on the 

 black ones, by which they are environed, glares out with a 

 splendid effect ; and, what is more interesting, you can 

 trace the manner in which they are set, — those of each 

 row slightly overlapping the bases of another row, like 

 slates on a roof, — and also the mode in which they are in- 

 serted. The clear horn-coloured membrane of the wing is 

 seen raised in shallow transverse steps (if I may use such 

 a term), so that if it were divided longitudinally, the edge 



