EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 137 



In the next stage studied^ the color has become almost as deep as in the 

 adult. A number of the scales projecting from the extreme tip of the wing over 

 the cilia are brown tipped; these are continued in a broken line through the cilia 

 to the tornus. Over the wing membrane near the apex, in the area which was 

 transparent in the earlier specimen, the scales are becoming dark tipped. These 

 scales are deepest toward the apex of the wing, becoming very pale gray toward 

 the tornus external to the oblique dorsal streak. A few scales along the costa 

 corresponding in position with the dark scales in the adult are beginning to show 

 darker tips. The scales margining the first and second costal streaks, which were 

 whitish before, are now faintly gray. The color is uniformly developed over the 

 whole margin and on the prolonged portion of the second streak. 



In a specimen a little further advanced than the one just described, the apical 

 dusting is almost as in the adult. This darker color does not quite reach the 

 tornus; that is, the external edge of the white dorsal streak is stih margined by 

 pale gray scales as before. The margins of the first and second costal streaks 

 have scarcely changed in color, but the scales in the prolonged portion of the 

 second streak have darkened more rapidly; they are decidedly gray but much 

 paler than those in the apex. The only new character which has appeared is 

 the dark line through the cilia. 



Lithocolletis hamadryadella Clem. 



In the earliest stage examined {Fig. 21)^ the basal third of the wing is almost 

 colorless. At the extreme base on the costal margin is a small patch of pale 

 yellow scales, and a little beyond it another similar patch. These two patches 

 of scales form Band I. Beyond these is a somewhat larger patch of pale yellow 

 scales. This is the inner portion of Band II; the line of scales which marks its 

 original outer limit in the adult (Fig. 77, PL IV) has not yet acquired any pig- 

 ment. Band III at this stage is represented by a rather narrow angulated band 

 which extends across the wing some distance before the tip of vein 16. The 

 white projects into its angle on the inner side. Band IV is composed of two 

 separate patches of yellow scales, one on the costa and the other on the dorsum. 

 Their pointed apices lie over the bases of veins 10 and ^^^ 



2 respectively, the normal position for Band IV, but - "^^ ^ ^^^ 



on the margins, they curve back toward the base so > 



that they are much farther removed from the tips of 

 the veins than usual. The middle of the wing to the ^^ 



apex is colorless. Band V + VI is represented by a ^^^- ^i- Early stage in the 



, 1 r* 1 'ii • rrn 1 1x1 development of color in the wing 



patch of scales on either margm. The dorsal patch of l. taadr^a^a. 

 originates just beyond vein 2 and extends over vein 



5; the costal patch originates on the cell about midway between veins 10 and 

 9 but extends obliquely outward so that the inner edge on the costa is just basal 

 to vein 9 and the outer edge just before vein 7. The white streak over the tip of 

 vein 7 is very narrow, and its corresponding dorsal streak is indistinct. The 



