EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 125 
and spots are to appear. The development of the pattern takes place very 
rapidly during the last part of the pupal state. The time intervening between 
the first appearance of a tinge of yellow on the wings and the emergence of the 
imago is largely dependent upon temperature and is often less than twenty-four 
hours. Development takes place more rapidly in day time than at night and 
is strikingly retarded during cloudy weather. 
Lithocolletis tiliacella Cham. 
In the first specimen examined, the wings were removed from the pupa at 
a very early stage of development. The yellow color is scarcely differentiated 
from the clear buffish white wing (Fig. 9). The only bands и т 
which can be distinguished are II, III апа IV. Band II pr c 
crosses the wing just before the tip of vein 12, thus occu- € == = EM 
pying its primitive and typical position. It is the palest | WES 
and least defined of any of the three bands present. Its Еш.9. Early stage in the 
outer edge is definitely defined, but its inner edge fades ipee ane NM 
into the clear basal part of the wing, the color being ex- 
tended farthest toward the base just within the costal and dorsal margins. 
Band III has also preserved its primitive position and form. It is somewhat 
darker than II, but uniformly colored throughout its breadth, the outer edge 
not darkened. Its width is scarcely greater than that of the clear band pre- 
оу ceding it. Band IV is the most deeply colored as well 
"^—ww——: as the broadest of the three bands; it is of the same 
breadth as in the adult. Even at this early stage it is 
> prolonged outwardly almost to the end of the cell. The 
Fic. 10. Later stage in entire apical part of the wing and cilia are of the 
the development of color ш (iere whitish color, there being no indication whatever of 
the wing of L. tiliacella. 
bands. 
The wing in the next stage examined shows considerable advance over the 
stage just described (Fig. 10). There has been a decided deepening of color, 
and the adult pattern has been laid down, with the possible exception of Bands 
VI and VII, which have not as yet been clearly differentiated as bands although 
there is a faint yellow tinge in a few of the scales in the apical portion of the wing. 
These bands are usually indistinct and sometimes absent even in the adult. 
Band I is united with Band II along the costa ; this condition was apparently 
not produced by the independent origin of Band I and its later fusion with II 
but by a uniform and gradual deepening of the wing below the costa. The 
outer edge of Band II is now somewhat bent outward in the middle, and the 
scales in the middle of the outer edge are beginning to deepen in color, thus 
foreshadowing the appearance of the dark margin, but there is as yet no brown 
pigment in the scales. Band III is also somewhat bent outwardly as in the 
adult, and its dark margin is present on the costa and dorsum only, the costal 
margining being much less distinct than the dorsal; neither extends more than a 
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