NO. 2 RECOGNITION AMONG INSECTS — McINDOO 45 



Wonfor (1868, 1869) found these scales on the wings of males, 

 belonging to several genera and he regards them as a sexual character. 



Mclntire (1871) reports having distinguished these scales from 

 the ordinary ones. 



Anthony ( 1872) also distinguished these scales from the other kind. 



Miiller (1877b) says that the male butterflies of the many species 

 which he examined are distinguished from their respective females 

 by the presence of these peculiar scales on the wings. The same 

 author (i877c-d, i878e) asserts that many male butterflies smell 

 their respective females from an unbelievable distance. He thinks 

 that an odor is emitted from these scales, and for this reason calls 

 them " Duftschuppen." From the manner in which they are grouped 

 he regards them as a good device for collecting the secreted liquid 

 and for preventing a too rapid evaporation of it. Their generic 

 differences are considerable and they vary somewhat in shape on 

 the front and hind wings of the same species, but their specific differ- 

 ences as a whole are insignificant. He regards them as a secondary 

 sexual character. Miiller (i878f, 1879a) describes the scent scales 

 found in the feltlike spots on the upper side of the male wings of three 

 more genera. 



Scudder (1877, 1881) asserts that these scales should be called 

 androconia because only the males have them. He says : 



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 In the highest butterflies, they are \ortg, slender and 



invariably feathered at the tip 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 Equites where also they have been supposed 



to be wanting they differ but little from the ordinary scales but are much 

 smaller and more coarsely striate. In the Urbiculce, where no one has hitherto 

 recognized them, they present the greatest variety in the same individuals ; 

 in one group (Hesperides) there are hairlike androconia, and others which 

 are exceedingly large and spindle-shaped. In the Astyei, besides hairlike 

 and gigantic androconia, there are usually some which are spoon-shaped, with 

 long handles. 



Weismann (1878) predicts that an etherlike oil is secreted in 

 the cells surrounding the bases of the scent scales. He imagines that 

 this secretion passes through the scales to the exterior because the 

 structure of the scales indicates a conducting device. The simplest 

 type of these scales is hairlike and it is penetrated by a single axial 



