KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 



47 



" Lyonnet has filled several quarto plates with representations of 

 these scales varying to almost every form taken from the wing and 

 body of the Goat Moth." 



The scales, most commonly, are more or less oval in outline, and 

 insecurely attached to the membrane of the wing by a short, obtusely- 

 pointed pedicel arising from the narrower end of the oval. The 

 broader end has. a margin entire, or showing dentations of varying 

 depth and number. These dentations may be so deep, and the 

 accompanying teeth so long and slender, that the term "fingered" 

 will better express the appearance. In size the scales vary in length 

 from .07 mm., Micropteryx, to .8 mm., Castnia sp., if we consider only 

 scales of such specialization as no longer preferably to be termed 

 scale-hairs, and exclude the scales on the outer margin of the wing, 

 which are always unusually long and slender. In width the scales 

 vary from a hair-like condition to .4 mm. as in Castnia sp. The 

 relation of length to breadth varies much; on Castnia sp. some scales 

 are just as broad as long, and some even broader than long. The 

 well specialized scales are flat (except in the case of androconia) and 

 are striated longitudinally, i. e. from base to opposite margin, these 

 striae being very regular as regards the distance between contiguous 

 lines. The distances 

 between the strice 

 vary from .0007mm. 

 as in Morpho sp. to 

 .004 mm. as in 

 Callidryas culnilc. 



Figure i, a group 

 of differing scales, 

 displays these sali- 

 ent points of outline 



The scales cover (in most Lepidoptera) the wings on both upper 

 and lower sides, and present varying conditions of arrangement on 

 the wing-membranes. In any one of the more specialized butterflies, 

 a Morpho, for example, this arrangement is remarkably uniform. 

 The scales are inserted, with their pedicels directed toward the base 

 of the wing in sub-parallel rows running transversely across the wing, 

 i. e. from costal to inner margin, and the scales in each row are 

 inserted at approximately equal distances apart. Each row is prac- 

 tically composed of two 



tiers of scales, an under ^s— " -^=^- -.-,T!^^^^^'^^ ~IL!!^'~~ ._ "~ J~J^z:^^l 

 and an upper tier: the "■■'^--^"^^^-^^~=-^=~=-^~^— ~^-^^~^'~=-^^^^-=~^^ 

 insertion cups of one Fig. 2. 



tiprarf>vprvQll•o•l-.^-^vhll^°^'^°^■''^™ °^ cross-section of portion of a wing, showing 

 liei are very Sllgntiy out arrangement of scales. 



a, scale of Tolype velleda 



"of Micropteryx aruucella. 



Fig. 

 b, scale of Castnia sp. 



