138 EVOLUTION OF COLOR PATTERN IN LITLIOCOLLETIS. 



cilia belonging to Band VII are all yellow with a few white scales here and 

 there extending into them. Bands VII, V + VI and IV are somewhat deeper 

 than Band III; Bands I and II are very pale, their paleness being caused by 

 the large admixture of colorless scales at this stage. 



In the next specimen examined, apart from a slight deepening of Band III 

 and those beyond it, the only changes observed are the following. The two basal 

 patches on the costa, belonging to Band I, show a slight admixture of brownish 

 tipped white scales. The third patch (Band II) is now faintly continued to 



the dorsum by a line of scattered yellow scales, and just 



1 ^^ ^'^^^ m beyond it, in the position normally occupied by the 



'7 '^'"'^ outer margin of Band II, is an angulated line of very 



faintly yellow scales. This marks the original outer 



, -' limit (phylogenetically) of Band 11. Just before the 



Fig. 22. Later stage in the tip of vciu 16 is a similar line of scalcs running parallel 



development of color in the wine , ,i i i r* t~» i ttt i i • -j i 



of L. hainadryadeiia. ^^ ^^^ dorsal arm 01 Band III and markmg its outer 



limit. These two lines of scales sometimes do not ap- 

 pear until a much later period in the development. Their time of appearance 

 is largely determined by the number of yellow scales mingled with the dark 

 scales in the adult, since it is only in the yellow scales that the pigment ap- 

 pears early. 



In the next stage studied (Fig. 22)^ Bands I and II in the basal part of the 

 wing remain practically unchanged. Band III is the same in extent, but its 

 color has deepened. Its internal margin is beginning to form, the scales adjacent 

 to the yellow becoming gray tipped. The gray pigment appears directly in 

 the whitish uncolored scales of the previous stage without passing through any 

 of the intermediate steps. In general, the margin is broadest on the costa, be- 

 coming narrower and paler below it, and not easily distinguishable toward the 

 dorsum. On its inner edge, the margin is straight or slightl}^ curved as in the 

 imago; on its outer side, the scales project into the angle of the band and fill 

 up the formerly colorless space. The tips of these scales are darker than those 

 of the margin elsewhere. In this specimen, there are only a few scattered yellow 

 scales beyond Band III and no indication whatever of the dark line of scales 

 which is to appear later. The internal margin of Band IV is well marked on its 

 dorsal half, consisting of several rows of dark tipped scales as in the imago. It 

 curves between the two yellow patches, extending to their apices, but not beyond 

 them into the colorless fascia. The costal half of the margin consists only of a 

 few pale gray scales and does not quite reach the dorsal half of the margin. 

 Except for a few very faintly grayish scales above the termen on the inner edge 

 of the dorsal part of Band V + VI, there is no indication whatever of any dark- 

 ening of scales adjacent to Band V + VI. Belonging to Band VII, and begin- 

 ning just behind vein 7, the scales covering the entire apex of the wing are gray 

 tipped. Some of them, especially on the costal margin, project over the yellow 

 scales which are to form the line in the middle of the cilia. The gray tipped 



