EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 135 



separates Bands I and II extends entirely across the wing, but the early fusion 

 of these bands on the costa is foreshadowed by the very faint tinge of buff just 

 making its appearance in the costal portion of the pale fascia. On the extreme 

 costa, Band V is indistinctly separated from VL Band VI is separated from 

 VII by a white streak extending entirely across the wing. With these exceptions, 

 the yellow marks are defined as in the adult. The white oblique dorsal streak 

 extends just within the termen, being separated from the white streak before the 

 apex as in the adult. The distal end of the oblique 



dorsal streak is probably homologous with the middle ^ ,-<- ' '^zjj:^..:-'^^'^ 

 portion of the white fascia which in primitive types ; . "" 



separates Bands Vand VL In the imago, it sometimes 



exists as a separate small white spot before the apical Fig. 19. Early stage in the 

 dusting and more proximal than the obhque costal development of color in the wing 



^ ^ PI 01 L. oBSCuhsella. 



streak. Along the termen, the cilia are of an unbroken 



yellow color, showing that at the extreme margin, there has been a complete 



fusion of Bands V, VI and VIL 



Before any of the dark margins begin to appear, the ground color deepens 

 into the orange yellow of the adult. The external margin of the second fascia 

 and the dark dusting at the extreme apex are considerably in advance of the 

 other dark markings. The margin of the second fascia, formed by a dark line 

 of scales along the inner border of Band IV, is most distinct in the middle 

 portion of the wing and has not appeared on the extreme dorsal end nor on the 

 costal end beyond the angle. Its color at this stage is brownish. In one speci- 

 men, the apical scales are not as dark as the margin of the second fascia; in another 

 of the same age, as indicated by the state of development of the margins, the 

 dusting of the apex is somewhat darker than the margin of this fascia; in both, 

 however, the brownish tint is confined to the extreme apex. There is a slight 

 darkening of the scales in the middle of the wing on the inner border of Band III 

 adjacent to the first white fascia and along the under side of the oblique dorsal 

 streak. 



The dark margins of the fascise and of the obhque dorsal streak continue 

 to develop, but before they reach their adult condition, the scales on the outer 

 side of the costal spot over vein 10 begin to darken. At this time, the apical 

 dusting is still confined to the apex of the wing and is not extended along the 

 termen toward the tornus. This extension of the dusting toward the tornus is a 

 characteristic of specimens appearing in the summer and does not occur in forms 

 from overwintering chrysahds. It develops after the other adult characters 

 have appeared. 



Lithocolletis bethunella Cham. 



In the youngest specimen examined, the ground color is a uniformly pale 

 ocherous, and upon it the extent of the adult markings (Fig. 84, PI. IV) is quite 

 definitely blocked out (Fig. 20). The white fascia (or second pair of streaks) 



