138 THE YOUNG NATURALIST. 



[July 



and the scale is then seen to be composed of longitudinal striae ; each 

 line formed by the cohesion of the granular particles. In the scales of 

 Lycana corydon, the granular nature of the striae is very evident, while 

 in the peculiar battledoor scale, so well-known as typical of the "blues," 

 the striae are not only few in number, but are interrupted at regular 

 intervals by expansions or enlarged granules (Fig. 12.) Another 

 point not shown in the figure, concerning these so-called " battledoor 

 scales" is that the striae are in many cases very imperfect : in fact, more 

 apparent than real. The dilatations are present but unconnected. 

 I have only been able to see this with an immersion lens of high power, 

 the best eighth objective being incapable of separating them. This 

 is largely due to the fact that low powers practically focuss both 

 upper and lower membranes, and as the markings are common to both 



Fig 12. Fig. 14. Fig. 13. Fig. 11. 



laminae, an incorrect image is the result. This remarkable scale is 

 only found on the male insect, never, as far as I am aware, on the 

 female ; and, moreover, only on the upperside. 



Reference to Fig. 10. (L. adonis) will show the position occupied by 

 them on the wing, and it will be noticed that an irregular row alter- 

 nates with the ordinary scales, which cover their long peduncles, 

 leaving only a portion of the spatulate enlargement visible. This 

 scale varies in contour somewhat, according to the species bearing it. 

 Thus in L. corydon (Fig. 12), we have an almost perfect oval, with an 

 elongated stalk, becoming rounder in L. anon, with the accompaniment 

 of an abbreviated pedicle. Those of L. alexis and L. argiolus are cut 

 off almost square at the tips. A most curious exception occurs in L. 



