THE WINGS OF LEPIDOPTERA 



323 





probably a provision for insuring the rapid evaporation of the product of 

 the scent gland. Androconia have been figured and described by many 

 authors. 



Associated with the patches of androconia there are frequently covering 

 scales of various forms. 



In many Lepidoptera the scales are lacking on portions of the wings; 

 familiar examples of this are most of the Sesiidas and certain members of 

 the SphingidoD. 



The clothing of fixed hairs. — In addition to the clothing of scales, 

 Kellogg ('94) discovered upon the wings of Micropteryx, which at that time 

 was believed to belong to the suborder jugate of the Lepidoptera, and 

 Hepialns "a covering of very fine hairs differ- 

 ing radically from the scales in size, arrange- 

 ment, and mode of attachment to the 

 membrane, and agreeing essentially with the 

 fixed hairs of the Trichoptera." 



Kellogg applied the term fixed hairs to 

 this type of clothing, as the hairs are directly 

 continuous with the cuticula of the wing 

 instead of being jointed at the base, as are 

 setas. The fixed hairs are much smaller than 

 are the scales. In Micropteryx unimaculella 

 they average .005 mm. in length, and are dis- 

 tant from each other at their bases a length 

 approximately equal to the length of the hairs. 

 The scales of M. unimaculella average from 

 .1 mm. to .15 mm. in length. In Hepialus 

 sylvinus, he found that the fixed hairs were 

 about one-tenth as long as the scales. 



As Kellogg was unable to find the fixed 

 hairs on the wings of any of the Frenatae examined by him he concluded 

 that their presence was a distinctive character of the Jugataj. 



In a paper published a year later, Spuler ('95), who evidently had not 

 seen Kellogg's paper, describes the fixed hairs under the name Stacheln, and 

 indicates their occurrence not only in the Micropter\^gidffi and the Hepialidae, 

 but also distributed over the entire wings in certain Tineids {Incurvaria, 

 Adela, Nematois, Nemophora, and in the Nepticulidas, and in limited areas 

 on the wings of certain other Lepidoptera, in what he terms the "Haftfeld" 

 or holding area, on the lower side of the inner margin of the front wing. 

 The "Haftfeld" of Galleria mellonella is especially mentioned. 



The fixed hairs are referred to by Busck ('14), in his paper On the 

 Classification of the Microlepidoptera, as the aculei; and the Lepidoptera 

 that are characterized by their presence on the wings are designated as the 



Fig. 332. — Androconia from the 



wings of male butterflies 



(After Kellogg). 



