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scales^ called plumules, have long been known ; but examina- 

 tion with the binocular microscope shows that they are not 

 flat like the ordinary scales, but cylindrical and hollow. 

 They have been found only in certain genera (named in the 

 paper) at present, and on the males alone ; they possess 

 generic resemblances and specific diflerences, each species 

 displaying its own distinguishing variety. One of great 

 beauty and novelty, found only on two African butterflies, 

 Pieris Agathina and Pieris Chloris, was described, and some 

 very fine drawings of it, by Mr. Joseph Sidebotham, were 

 exhibited, and also other figures by him of about one hundred 

 species never figured before. The names and habitats of the 

 insects were given, and the Author pointed out the value of 

 these scales for the assistance of the scientific entomologist 

 in arranging genera and species; he then entered into the 

 question of their probable use as air vessels in the economy 

 of the insects possessing them. 



The Chairman remarked that the scales of the Lepidoptera 

 may prove to be as valuable in determining species as the 

 scales of fishes. 



Mr. Sidebotham alluded to the value of the binocular 

 microscope in defining the cylindrical form of the plumules, 

 and described the mode of finding them in situ, by breaking 

 the wing. 



Mr. Watson stated that some of Mr. Sidebotham's excel- 

 lent drawings were taken under the eighth objective, magni- 

 fying 750 diameters. Mr. Watson further said that he had 

 examined the wings of 400 specimens of the Papilionidse, 

 but had not discovered any plumules in that genera ; he also 

 alluded to several so called species from South America, of 

 which no males have yet been found, others of which no 

 females have yet been discovered, and suggested the possi- 

 bility of some of these being male and female of the same 

 species ; to ascertain which, careful examination of the scales 

 might be useful. 



