EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 123 
3. Observations. 
Two factors were taken into consideration in determining the choice of species 
to be studied, namely, the general type of adult marking and the presence or 
absence of certain characters such as an apical spot or dark marginings adjacent 
to white streaks or fascia. The object of the research is twofold: (1) to deter- 
mine, if possible, the primitive or fundamental color pattern and its mode of 
transformation into the adult pattern and (2) to determine the relative time of 
appearance and manner of development of the various dark markings, the 
characters referred to above. 
The evidence furnished by the development of color in the pupal wings 
taken in conjunction with a comparative study of the adult markings has con- 
vinced me that the primitive color pattern is composed of a series of uniformly 
colored pale yellow ban ds, seven in number, placed transversely on the wing and 
separated from one another by white fascize (unpigmented areas) (Fig. 8). These 
bands are typically straight and, with the exception of 
the first, cross the wing almost perpendicular to the mar- МО ЧИ. С T. 
gins. The bands, when present in their primitive con- t Жш а сна 
dition, have certain defined positions. Their hypothetical > AL. NA S 
typical positions are illustrated by Fig. 8. In what fol- з» We 
lows, it will be noticed that there is a definite relation : AL 
Ч К Fra. 8. Hypothetical primitive 
of bands to veins. Band I occupies the extreme base color pattern of the forewing of 
of the wing, beginning at the base of the dorsum and Lithocolletis. 
broadening on the costa; the white streak which sepa- 
rates it from Band II passes obliquely from the base of the dorsum toward 
the costa, lying over the point of origin of the tubular portion of the lower 
median vein. Band II crosses the wing on the basal side of the tip of vein 
12; the position of the white fascia which separates it from Band III seems 
to be determined rather by the point of origin of the tubular portion of the 
upper median vein than by the tip of vein 12, as this vein often extends con- 
siderably beyond the origin of the upper median vein without causing a cor- 
responding broadening distally of the second band. It sometimes happens 
that vein 12 is unusually short, and then the white fascia lies over its tip and 
over the origin of the upper median vein. On the costa, the inner border of 
Band III lies just beyond the origin of the upper median vein, and on the dorsum, 
the outer border extends almost to the tip of vein 1b. Band IV crosses beyond 
the tip of vein 1b and lies over the bases of veins 10 and 2, its outer border being 
just within the tips of veins 10 and 2. Band V on the costa is placed between 
veins 10 and 9, on the termen between veins 2 and 5 and lies over the transverse 
vein. Band VI is placed between veins 9 and 7 on the costa and beyond vein 5 
on the termen. Band VII crosses the apex of the wing. "Thus it will be seen 
that the position of the bands is largely determined by the position of the longi- 
tudinal nervures, the tips of the veins marking the extremities of the unpig- 
mented fasci# separating the bands. In no case in the adult has this pattern 
