254 PROCEEDINGS OF THE AMERICAN ACADEMY 



siderably in color. Nevertheless the imagos were all alike. The 

 caterpillar of Hemileuca Maia feeds in Michigan, New York, and 

 Massachusetts on shrub oak {Q. ilicifolia), in Maine and in Nevada (?) 

 on SpircBa salicifolia. The caterpillars are very little different, but 

 the imago differs considerably. The first ones are largely black, with 

 more or less narrow white bands ; the last ones are largely white only 

 with blackish borders, and sometimes the hairs on both sides of the 

 front part of the thorax are also snow white. 



Rev. H. H. Higgins (Quart. Journ. of Science, 1868, vol. v. pp. 323 

 -329, pi. 1) gives some remarks on the proximate origin (the appliances 

 immediately engaged in producing the color pattern) and general con- 

 figuration of the patches, bands, and spots of color on the wings of 

 Rliopalocera. " In the chrysalis state the pritterns of the closely folded 

 wings, the like spots on the right and left wings do not coincide; that 

 v.'hich becomes a beautifully formed band, begins as a mere line or 

 a shapeless spot. The simplest type of color presents itself in the 

 plain uniform tint when the scales are all colored alike, which is 

 comparatively rare. At first the scales growing on the membrane 

 upon or near the veins show a fi-eer development of pigmentary 

 matter, and in this manner would arise a kind of jDrimary or funda- 

 mental pattern, namely, a pale ground with darker linear markings, 

 following the course of the veins (Pi'eris cratcegi). This pattern 

 occurs in most of the families. Let it be supposed that at a given 

 distance from the base a portion of the dark scales begins to diverge 

 on each side from the veins. The dark lines thus formed will meet 

 in the middle of the areas between the veins producing a band of 

 scallops having their concavity towards the base of the wing. A 

 similar band nearer to the base would have its convexities in the same 

 direction. If the latter mode of divergence be quickly followed by 

 the former, a row of annular markings between the veins is the result, 

 the simplest form of annular or ocellate spots. In the pupa state the 

 scheme of the future pattern is fully organized, so that by the exten- 

 sion of the soft wings the pattern of the imago is easily performed. 

 From the vein scales arise all the darker markings, enclosing some- 

 times the areas of pale, ground tint. The modifications of those areas 

 are performed by a blush, the deepening or the intensifying of the 

 color in certain parts of the wing ( G. Cleopatra) . Besides this comes 

 the gloss by iridescence." 



Charles Darwin (Descent of Man, vol. ii. pp. 126-127. fig. 52) speaks 

 of the formation and variability of the ocelli on the wings of many Lepi- 



