120 EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 
‘blood’ or hemolymph of the pupa enters them, and soon after this, the wing 
becomes of a uniform dull yellow or light drab color. This color is due to the 
fact that soon after the hemolymph has entered the scales, it changes to a dull 
ochre-yellow and finally to a drab color. The same change takes place in hzemo- 
lymph which has been removed from the pupa and exposed to the air. The 
mature colors are due to chemical changes in the hemolymph itself. They 
first appear in places between the nervures, never upon the nervures themselves. 
The last places to acquire the mature coloration are the outer and costal edges 
of the wings and the nervures. . . . 
“Dull ochre-yellow and drabs are, phylogenetically speaking, the oldest 
pigmental colors in the Lepidoptera, for these are the colors that are assumed by 
the hemolymph upon mere exposure to air. The more brilliant pigmental colors, 
such as bright yellows, reds, greens, etc., are derived by more complex chemical 
processes. We find that dull ochre-yellows and drabs are at the present day the 
prevalent colors among the less differentiated nocturnal moths. The diurnal 
forms of Lepidoptera have almost a monopoly of the brilliant colorations, but 
even in these diurnal forms, one finds that dull yellow or drab colors are still 
quite common upon those parts of their wings that are hidden from view." 
The most recent researches upon the subject of development of color in 
the pupal wings of Lepidoptera are those of von Linden (798, '02). The results 
of her investigations are embodied in two papers, the first being practically in- 
cluded in the second. Her observations lead to the conclusion that the adult 
color pattern develops from a number of separate transverse bands which dispose 
themselves upon a uniform ground color in a manner characteristic of each 
species. A distinction is thus made between ground color and that forming the 
color pattern. These transverse bands (longitudinal according to Eimer's view) 
oceupy definite positions upon the wing determined by the course of the nervures 
and tracheæ. This is the condition found among Papilios, Vanessas, Sphingids, 
the higher Bombycids and even among some of the Geometrids. "These larger 
bands are formed by the broadening out and fusion of narrower bands (‘‘bande- 
lettes primaires") preserved only among more primitive forms. On the one 
hand, the bands may fuse to form a uniform color; on the other, they may break 
up into a series of spots, which become smaller as the ground color encroaches 
upon them. The hindwing is arrested at a point less advanced than the fore- 
wing; this, combined with the greater tendency toward fusion of the bands 
which is in fact due to the modified form of the hindwing, creates the erroneous 
impression that the hindwing is more advanced than the forewing. 
The author claims that her results support the laws which Eimer has promul- 
gated for species differentiation based upon a study of adult coloration: 
“Tl est donc évident que les lois que Eimer a trouvées en étudiant la phylogenése 
du dessin des Lépidoptéres peuvent étre admisés point pour point pour l'ontogenése. 
“Mes reserches preuvent done que le dessin des Papillons ne parait pas 
soudainement, . . . que les phases que ce dessin parcourt pendant son developpe- 
