KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 8l 



wings, in addition to the covering of scales. (For a detailed 

 account of the characteristic wing-covering of Jugate, see pp. 60, 61.) 

 This covering of fine hairs is the persistence of a primitive wing- 

 covering, probably approximately represented in the wing-covering of 

 the living Trichoptera. These fine, fixed hairs are wholly wanting in 

 the Frenatae, having disappeared in even the most generalized of the 

 living Frenatae. This suborder comprises two families, the Hepialidte 

 and the Micropterygidne. 



HEPIALID^. 



The only North American genus of the family is Hcpialiis. The 

 moths of this genus are mostly dull-colored, without sharply defined 

 color-markings. There should be excepted the silvery white spots 

 present on the forewings of a majority of the species. These white 

 spots are sharply delimited, and are caused by scales containing air. 

 The ground color of the forewings varies from grayish-brown to 

 testaceous to reddish-brown, and the markings consist of broad 

 irregular bars and large uneven blotches. The hind-wings are almost 

 uniformly dully uni-colored, rarely exhibiting indistinct markings at 

 the apex, as in argenteomaculatus 



The scale covering of the hindwings is markedly less specialized 

 than that of the forewings, the advance of the forewings depending 

 doubtless on the special development of color-markings, as the 

 venation of the fore and hindwings is almost identical, so that the 

 flight-use of the wings is about equal. 



The line of scale-specialization in Hepialus appears to be this: 

 The long scale-hair flattens, widens and shortens; the tip shows an 

 angular emargination, a shallow dividing; the widening and short- 

 ening of the scale-hair continues, and there is a further dividing at the 

 tip into three or four or five short, sharp-pointed wide-based teeth. 

 The scales are pigmented and show what may be called a double stria- 

 tion, i. e., a few coarse, heavy stri;x' are interspersed among the more 

 numerous ordinary fine stria;. In dentate forms there are as many 

 heavy striee as there are marginal teeth, each stria terminating in the 

 point of a tooth. This double striation is not plainly apparent in 

 some of the scales when they are mounted dry, but is well brought 

 out by mounting in balsam. Whether these coarse striae are due to 

 an extra thickening or folding of the cuticular membrane, or by a 

 special aggregation of pigment granules in regular lines is undeter- 

 mined. 



The specialized scale, therefore, in a majority of the species of 

 Hepialus is rather elongate, with a few short, sharp-pointed, wide- 

 based teeth on the outer margin. The scale is pigmented and doubly 



