TKK 



&* 



is.*''' 





VOLUME II. 



ON THE MICROSCOPICAL EXAMINATION OF THE PLUMULES, &c., OF 

 CERTAIN DIURNAL LEPIDOPTERA, AS A MEANS OF SPECIFIC 

 DIAGNOSIS. 



BT JOHN WATSON. 



The plumules are found only in the male sex, and appear to be 

 hollow balloou-like bags, well adapted to act as air vessels ; they lie 

 between and under the rows of the ordinary scales, which they may 

 raise, when inflated, at the will of the insect, and thus give greater 



buoyancy. Each plu- 

 mule is attached to the 

 wing by a peduncle and 

 bulb, through which air 

 may be communicated 

 to the nervures ; the 

 opposite end possessing 

 eUia calculated to act as 

 in the spiracles of in- 

 sects.* 



It is specific, not 

 generic, distinction 

 which seems to be es- 

 tablished by an exami' 

 nation of theseplumules; 

 for although a generic 

 type may apparently 

 sometimes occur, it 

 blends into others ; and, 

 like any single character 

 of a genus, is not abso- 

 lutely trustworthy. The 

 specific distinctions, 

 however, are manifest 

 and decided. 



* For further information on this interesting subject, tlie reader is referred to a paper (also by 

 Mr. John Watson) " On cbktain Scales of Diukn al Lepidoptera," published in the second volume 

 of tlie third series of Memoirs of the Literary and Philosophical Society of Manchester, 1&61-2.— Eds, 



1. Pieris napi 



2. Pieris cratsegi 



3. ,\nthocari3 cardamines 

 4 Lycsena Corydon 



5. Lyctena^gon 



fi. Lycsena argiolus 



7. Erebia Blandina 



8. Argynnis Atrlaia 



9. Satyrus Megaera 



June, 1865. 



