MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 51 



MELANISM IN THE WHITE AND ROCKY MOUNTAIN AND PACIFIC COAST MOUNTAIN REGIONS. 



Without at present entering into the discussion of the general causes of melanism, we will 

 draw attention to such cases as have fallen under onr notice in the present group. 



It seeuis generally recognized, however, that nieUmism is due to elevation (not necessarily a^ 

 high latitude) united with an excessively humid or wet climate. We have such elevated areas over 

 which the rainfall is excessive in the White Mountains, in the Adirondacks, in the mountains of 

 British America, the Cascade Range and its spurs in British Columbia, Washington, and Oregon, 

 and in the elevated portions of the Sierra Nevada and of the Rocky Mountains, with their subordi- 

 nate ranges and spurs. In such a cool and moist climate we also have much cloudy weather and 

 far less direct sunlight than on the drier and more sunny lowlands. This does not exclude the 

 fact that melanism may occur in a low and wet region, as the west coast of xVfrica. 



Mrs. Slosson, who has spent numerous summers iu Franconia, N. H., aud has had wide 

 experience in collecting Lepidoptera in that region, as well as in Florida, informs me that it is 

 almost invariably the case that the White Mountain moths are darker aud richer in hue than 

 southern individuals of the same species. 



The following facts bear on this point: 



"But it is also a known fact that many species of animals, especi.ally of insects, which are 

 found at a high level on mountains have a darker coloring than their allies at a lower level. Thus 

 there are remarkably dark species and varieties of beetles occurring at high levels." (Elmer's 

 Organic^ Evolution, p. 9ti.) 



The late Dr. Weinland, who lived some years in the United States, remarks, as quoted by 

 Eimer, " that darker pigment is always produced on mountains, as in Vqjera prester, the Black 

 Mountain variety of Vijfera benis, as in the black rattlesnake of the White Mountains iu North 

 America" (Ibid., p. 98). 



Eimer thinks only two causes, apart from moisture, aid iu the production of dark hues in Alpine 

 animals, i. e., " either light or decreased atmospheric pressure." But is not the cloudiness and 

 dullness of the skies about mountain summits, i. e., the absence of sunlight as compared with the 

 bright sunny days of the lowlands, sufficient, with moisture, to account for the increase in dark 

 pigment ? Though, to be sure, the heat and moisture of the west coast of Africa cause the greatest 

 extreme of melanism iu the negro races. 



Cases of melanotic forms, both in the Eocly Mountains and on the humid, cool portions of the Pacific 



Coast, and on the Atlantic Coast regions. 



Gluphisia severa var. slossoniie (White Mountains). 



Ichthyura brueei var. multnoma (Oregon and Washington). 



Pheosia dimidiata var. portlandia (Oregon and Washington). 



Notodonta straguhi var. pacitica (California). 



Hetcrocampa guttivitta. Franconia, N. H. 



Cerura multiscripta. In the Northeastern States. 

 It should be noted that Cerura seitiscripta is represented in New England by the dark form 

 C. multiscripta. 



It is greatly to be desired that hereafter collectors working in the Eocky Mountain regions, as 

 well as anywhere in the Campestrian region, including the Pacific Coast, should carefully state on 

 their labels the exact locality, with date (at least' the month), of their ca^jtures. 



Vll.— ON THE PHYLOGENY OR CLASSIFICATION OF THE LEPIDOPTERA. 



It hardly need be said that the classification of the Lepidoptera is in a very unsatisfactory 

 state. This is due largely to the fact that the group is so homogeneous, that the habits and 

 environment of the species are so uniform, and that the adaptive modern characters have hidden 

 the slight primitive or ancestral characters which crop out in certain forms; hence the phj'logeny 

 of the order is difficult to unravel. It is now perhaps generally supposed that the Lepidoptera 

 have originated from the Trichoptera, or from forms very much like them, the most generalized 

 Tineina being closely similar to the caddis flies, though we shall endeavor to show that this view 



