o02 ON THE SCALES ON THE WINGS 



uniform texture, and without striae. Having seen thus much 

 in this dehcate and nearly pellucid scale, it naturally occurred 

 to me that I might at least confirm, if I did not add fresh facts 

 to those already acquired, if I selected as my next subject for 

 examination a description of scale whose striation was of a 

 bolder character, and which at the same time was possessed of 

 a greater degree of colour; and I accordingly fixed upon 

 Pap'dio Paris as possessing, in an eminent degree, both of the 

 requisite qualities. 1 proceeded in the preparation of this 

 subject in a manner precisely similar to the former, and in this 

 case the results were in every respect most satisfactory. In 

 the first scale examined, a fracture of the striae, and of the 

 upper dark-brown and almost opaque membrane, had taken 

 place at about one-third of the length of the scale above the 

 base, which extended nearly thi'ee-fourths across its greatest 

 breadth, in one direction, and to the base of the scale in 

 another. A portion of the disrupted striae and upper mem- 

 brane was doubled backwards, the plait or fold forming a 

 diagonal across the direction of the longitudinal striae, by 

 which means the striae thus doubled back were laid over the 

 others, nearly at right angles to them, and a small portion of 

 the fractured ends projected beyond the margin of the scale. 

 The portion thus doubled back rendered that part of the scale 

 beneath it nearly impervious to the light, while that from which 

 it had been lifted became beautifully transparent ; it scarcely 

 possessed any colour, and, at the same time, was without any 

 indication of striae ; thus confirming, in a very happy manner, 

 the observations previously made upon the scales of Morpho 

 Menelaus. Upon mounting the scales of the same insect in a 

 similar manner to that last described, upon a second slip of 

 glass, another case presented itself which threw still further 

 light upon the true structure of these minute and beautiful little 

 objects. In this instance a piece of the upper dark-brown 

 layer of the scale, being about half its length and one-third of 

 its width, was removed, leaving the part thus denuded nearly 

 without colour, while the surrounding uninjured portion of the 

 scales was of a blackish-brown tint, and nearly impervious to 

 the light, but distinctly exhibiting the striation. Upon one- 

 half of the pellucid space thus produced the striae were pre- 

 served uninjured, and in their natural situation, while from the 

 remaining space they had been totally removed, leaving the 



