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T EIC en NEP E ERE IIS TET ы ee NR EN TS E eur РАЛЕ E Ld و‎ iau: 
EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 127 
is present in the adult; that is, Band IV has not yet begun to extend outwardly 
through the cell. The space separating V + VI from VII is at this stage about 
one-half the width of V + VI and extends entirely across the wing, thus differing 
strikingly from the condition found in the adult. 
The development for some time consists merely in a uniform darkening of 
the ground color as first laid down without any change in the extent of the bands. 
At a somewhat later stage, simultaneously with the darkening of the ground 
eolor into the adult shade, changes in shape and more complete fusions of some 
of the bands occur. As soon as the adult color has been attained, the dark mar- 
gins begin to develop. А specimen examined at this period shows that while 
no change has taken place in the form or extent of Bands I + II and III, Band 
IV has become outwardly angulated as in the adult, thus narrowing, especially 
in the middle of the wing, the white fascia separating it from V + VI. On the 
dorsal margin, Bands V, VI and VII are completely fused, the small white costal 
streak before the apex alone remaining to mark the position of the white fascia 
between V + VI and VII. The scales along the outer edges of Bands II and 
III are beginning to show faintly brownish tips, this color being about evenly 
distributed along the entire edge of Band II; in Band III, the color extends 
farther toward the bases of the scales in the middle of the wing. The scales of 
the dorsal half of the outer edge of Band IV are dark reddish brown, almost as 
in the adult, but on the costal half of the wing, there is only a very slight deepen- 
ing of the yellow color, the margin here being considerably paler than the margins 
of Bands II and III. "There is a very slight deepening of scales on the outer 
border of Band V + VI, adjacent to the white streak before the apex. The 
dusting in the apex is dense, the color being darker and more blackish than the 
outer margin of Band IV, and extends from the white streak well around the 
apex and along the dorsal margin almost to vein 5. This dusting is considerably 
greater in extent even in this stage than that of the overwintering forms in any 
stage. 
Lithocolletis crategella Clem. 
This species belongs to that large group in which the imago is characterized 
by the presence of pairs of opposite white costal and dorsal streaks; that is, all 
of the original primitive bands have fused at least along the middle of the wing. 
L. crategella (Fig. 36, Pl. III) possesses in addition a margined basal streak, ex- 
ternal as well as internal margins to the white streaks (7. е., the dark scales 
developed on both sides of the primitive bands and not only on the outer side, as 
in the two preceding species), a streak of dark scales along the middle of the 
wing, a patch of black scales in the apex and the blue iridescence of the scales in 
the cilia. The study of the development of the wings in this form should there- 
fore throw light upon the origin and mode of development of the above characters 
and indicate their relative time of appearance. 
In the earliest stage examined (Fig. 12), at a period when the markings are 
