OF ARTS AND SCIENCES. 157 



cliarms are greatest. He certainly brings powerful argument and a 

 strong array of facts to support this hypothesis ; but what then shall 

 be said of tlie following ilhistration of structural antigeuy ; viz., the 

 presence iu many males, but in no females whatever, of scales of 

 the most exquisite beauty and delicacy, scattered among tlie more 

 common sort, and invisible to the naked eye ? Even with the help of 

 the microscope, they can often only be discovered by ruffling the wing, 

 and forciljly extracting them from their concealment; and, so far as 

 we can see, they give to tlie wing no peculiar character by which it 

 may be distinguished from other wings. 



These peculiar scales, or androcouia, as they may be called in ref- 

 erence to their masculine nature, were first noticed by Bernard 

 Deschamps more than forty years ago,* but have never been properly 

 studied tliroughout the butterflies. Deschamps called them plumules, 

 from their feathery tips ; but the term is utterly inappropriate to most 

 of them ; and their form is so varied that only some word expressing 

 their masculine character should be accepted, since this is their single 

 common peculiarity. 



These androconia are very capricious in their occurrence ; a number 

 of allied genera may possess them, while a single genus, as closely 

 allied, may be quite destitute. This is true throughout the butterflies, 

 and yet there are large groups in which they are altogether wanting, 

 and others in which their absence is extremely rare. In the highest 

 butterflies, they are long, slender, and invariably feathered at the tip. 

 In one small group (the Hdiconii), they are toothed as well as feath- 

 ered. With the exception of the Heliconii, they may generally be 

 distinguished from ordinary scales by the absence of any dentation 

 at the tip. In the Voracia, they are fringed, and, with a single known 

 exception, their extreme base is expanded into a sort of bulb ; else- 

 where, even in the other Pierids, they are not fringed, but have a 

 smooth rounded edge. In the Adolescentes they assume a battledore 

 or fan shape, with a smooth edge, and are generally beaded, and more 

 heavily striate than the scales. The same is true, but with more vari- 

 ations, in tiie Villicantes and Ephori, where they have been considered 

 wanting. In the Equites, where also they have been supposed to be 

 wanting, they differ but little from the scales, but are much smaller 

 and incjre coarsely striate. In the Urblcolce, where no one has hitherto 

 recognized them, they present the greatest variety in the same individ- 



* Recherches microscopiques ?ur I'organlsation des ailes des Le'pidopteres, 

 Ann. Sc. Nat. [2] III. 111-37 (1835). 



