KELLOGG: TAXONOMIC VALUE OF SCALES OF LEPIDOPTERA. 53 



Burmeister* based on a careful examination of the scales of Castnia. 

 He says that the two outer membranes of the scale do not enclose a 

 third lamina, but claims that the scales are empty, " contenant 

 seulement de Fair dans I'interieur * * * Dans les colorees [pig- 

 mented] ce vide contient une matiere fluide au commencement de 

 la formation de I'ecaille, qui desseche peu a peu par I'infiuence de 

 I'air atmospherique et laisse un depot sur la surface interieure des 

 deux lames de I'ecaille; enfin le fluide remplac^ par I'air atmospherique 

 qui est entre peu a peu par la resorption de la membrane, encore 

 molle, imm^diatement apres la formation de I'ecaille." Burmeister 

 believes that the striated appearance of the scales is due to the 

 presence of filaments which project into the interior of the scale from 

 the inner side of the outer membrane: "II n'est pas douteux que les 

 stries bien visibles des ecailles soient des fillets ^lev^s au cot^ interne 

 de la lame superieure, se prononcant au c6t6 externe seulement 

 comma strips fineraent imprimes. " My observations of sectioned 

 scales show this not to be the case. Minot and Burgessf also call 

 attention to this declaration of Burmeister as not sustained by their 

 observations. 



III. 



An inspection of the scales of the Lepidoptera will reveal, as 

 already remarked, a considerable variation in size and outline, but 

 reflection will convince the observer that the extremes of this varia- 

 tion in outline are reached when on one hand there is taken a long, 

 slender, hair-like scale such as those characteristic of the hindwings 

 of Mcgalopyge crispata, and on the other hand there is taken the 

 stiff, fiat, symmetrical scale plainly divided into short, sub-cylindrical 

 pedicel and broad, striated blade characteristic of the forewing of 

 Danais archippus. There are forms long and slender but widening 

 at the tip and having two or more points or teeth, as in Actias luna; 

 forms with short, wide blade with its outer margin entire as in 

 Microptcryx, or presenting several short teeth or points, as in Castnia 

 sp., or with several long, tapering fingers as in Tolype velleda. Nor 

 is it necessary to search among different genera or species to obtain 

 a large series of varying outlines: they may often be found on one 

 wing of a single moth, though there is a suggestive uniformity of 

 essential character about such a series of forms. Such a series of 

 gradatory forms from the forewing of Megalopyge crispata is shown 

 in figure lo. 



♦Burmeister, H.. '-Examen special des Ecailles." pp. 21-28 in Description Physique dg 

 la Republique Ai-gentine, 5me. touie (Lepidopteres), Ire. partie, 1878, Buenos,- Ayres, 



tMinot and Burgess, loc. cit. 



