300 ON THE SCALES ON THE WINGS 



autumnal weather we sometimes have in England in September 

 and October, but warmer. I staid four days at St. Augustine, 

 and then returned to Jacksonville, staying a day at Picolata on 

 the way. 



Art. XXX. — On the Structure of the Scales on the Wings 

 of Lepidopterous Insects. By James Scott Bowerbank, 

 M.E.S., &c. 



Having for many years been in the habit of using the scales 

 from the wings of various insects as a means of testing the 

 defining power of the object-glasses of microscopes, and in 

 particular those from Morpho Menelaus, I had long been 

 induced to suspect that, with a higher power than we could at 

 that time command, the delicate longitudinal and cross striae 

 of these scales might, probably, be demonstrated to be a series 

 of tubes, destined to serve, in each scale, the same office that 

 the canals, which are seen ramifying in every direction in the 

 wings of Hemipterous and other similar insects, perform for 

 those parts. Having lately been furnished, by Mr. Ross, with 

 an object-glass of his construction, possessing the requisite 

 increase of magnifying power, combined with the most perfect 

 and beautiful definition, I was induced to recommence my 

 observations on the scales of Morpho Menelaus. 



It has usually been the custom, when mounting the scales 

 from the wings of this insect for microscopic observation, to 

 breathe upon the slip of glass, so as slightly to moisten its 

 surface; then to lay the wing gently upon it, and press it 

 lightly once or twice with the tip of the finger, in order to 

 disengage a few of the scales with as little injury to them as 

 possible ; and, finally, to cover them with a thin slip of talc. 

 By this means, it will be evident that they will probably 

 present themselves in as perfect and unbroken a state as it is 

 possible to procure them, and with their under-sides towards 

 the observer. Having frequently examined them when mounted 

 in this manner, and iound that, even with the greatest degree 

 of care and the gentlest treatment, some of the striae were 

 crushed and displaced, and the scales thereby spoiled as a 

 microscopic test-object; and having often seen the remains of 



