OF SOME DIURNAL LEPIDOPTERA. 65 



tips projecting between the common scales ; they are easily- 

 detached, and in removing them the bulb is very liable to 

 be broken off; they are much more numerous on some 

 species than on others, and their number varies considerably 

 even on individuals of the same species, especially at dif- 

 ferent periods of existence. The males alone possess them ; 

 none are ever found upon the females. They have been 

 called '^ plumules " by some authors ; and those of Pieris 

 BrassiccB, P. RapcRj and P. Napi (our common white garden 

 Butterflies) are well known to microscopists, and were 

 formerly called test-objects. 



In the ^ Annales des Sciences^ for February 1835, there 

 is an interesting article on the organization of the scales of 

 Lepidoptera, by M. Bernard Deschamps. It is principally 

 devoted to the consideration of the structure of the scales, 

 as composed of several lamellae or membranes, of the mode 

 in which they are affixed to the wings, and of the place in 

 which the colouring matter is deposited. He also refers 

 to these plumules, and gives figures of a few of them : he 

 does not suggest any peculiar use for them, but draws atten- 

 tion to the fact that the males alone possess them, and that 

 they have some general resemblance, with certain specific 

 differences. He examined and figured seven species of the 

 Pieridse, to which family I am about to allude. My ffiend 

 Mr. Sidebotham has most kindly and laboriously drawn the 

 plumules of about one hundred species of Pieridse observed 

 by me, very few if any of which have been figured before. 



The most remarkable of these forms are represented on 

 Plates II. & III. ; and a list of the names of the genera 

 and species to which these forms of scales belong is ap- 

 pended to the paper. 



To the same gentleman I am also indebted for many 

 valuable suggestions carried out in the preparation of this 

 paper. It must be understood that the drawings are not 

 made to scale with any one power of object-glass; the 



SER. III. VOL. II. F 



