2 [June, 



In every (male) specimen of a species the plumules are the same ; 

 while the differences between those of different species are such as to 

 prevent any difficulty in identification : hence they are very useful in 

 determining whether any given insect be worthy of the rank of a spe- 

 cies, or whether it be merelj' a variety. 



In the genus Pieris the plumules of P. rapce and na'pi have long 

 been known and figured. An extended examina(;ion of this genus proves 

 that each species possesses its own characteristic plumule, by which it 

 can be identified with even greater certainty than by other appearances. 

 In the PieridcG there are generic types in great variety, besides that of 

 Pieris ; and thus in Anthocaris, Thestias, Euterpe, JUronia, and Heho- 

 moin, somewhat similar plumules are fouud ; that of each species having 

 its own identifying form. 



A different type is found among some genera of the Heliconidee, 

 each species again with its own. 



Among the Nymplialidce several groups are furnished with plu- 

 mules : the connecting links between the Nymplialidce and Heliconidce, 

 viz., Mucides and Golcenis having plumules similar to, and yet distinct 

 from, those of Heliconia : Agraulis exhibits a very singular plumule ; 

 and it is especially interesting to observe the specific differences in those 

 of the large group Argynnis ; while, strange to say, plumules have not 

 been detected on any species of the genus Melitcea. A similar apparent 

 inconsistency exists in the closely allied genera Neptis and Athyma, the 

 former being without plumules, and the latter possessing them. 



The Satyridce are, in some genera, abundantly clothed with plumules, 

 but it is remarkable, that while some species of a genus {Erelia, for 

 instance,) display these tests, many others are without them ; so it is 

 with Satyrus, in which the plumule of S. Janira has long been used as 

 a microscopic test-object. 



Among the Lyccenidce the genus Lyceena possesses the so-called 

 " battledore scales," long known to microscopists, but not before men- 

 tioned as affording any trustworthy test between species. These, and 

 the plumules of the Pieridce, are certainly the moat interesting of these 

 organizations. The closely allied genus Thecla has not been found to 

 possess plumules. In the great family Papilionidce, and in the 

 Dana'idce, none of these plumules have yet been discovered ; but the 

 subject (one which will repay any Naturalist who will pursue it,) has 

 only lately been entered into with zest. 



The delicai e beauty of these objects, their various forms, and their 



affinities, afford au endless interest, heightened by a consideration of 



the physiological fact that Creative Power has revelled in so great a 



variety of these minute atoms ; though, in all cases, with the same 



apparent end in view. 



Bowdon, April 6th, 1865. 



