MEMOIKS OF THE ^•AT10NAL ACADEMY OF SCIENCES. 51 



MELANISM IN THE ^VHITE AND ROCKY MOUNTAIN AND PACIFIC COAST MOUNTAIN REGIONS. 



W'itlioiit at present eutering into the discussion of the general causes of melanism, we will 

 draw attention to such cases as liave fallen under our notice in the present group. 



It seems generally recognized, however, .that melanism is due to elevatiou (not necessarily a 

 high laritn(h^) united with an ext-essively humid or wet climate. We Imve 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 aiul of the Rocky Mountains, with their subordi- 

 nate ranges and spnis. In such a cool and moist climate we also have much (doudy weather and 

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

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



.Mrs. Slosson, who has spent numerous summers in Fraiu;»nia, N. H., and has had wide 

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

 almost invariably the case that the White iMountain moths are darker and 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, especially 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 Evolutiou, p. 9L>.) 



The late Dr. Weinlaud, who lived some years in th.e United States, remarks, as quoted by 

 Eimer, '■ that darker pignumt is always i)roduced on mountains, as in Vipera ijrcster, the Black 

 Mountain variety of Vijferu berm, as in the black rattlesnake of the White Mountains in North 

 America" (Ibid., p. 98). 



Eimer thinks only two causes, apart from moisture, aid in the production of dark hues in A]i)ine 

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

 extreme of melanism in the negro races. 



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



Coast, and on the Atlantic Coast regions. 



Gluphisia severa var. slossoniie (White Mountains). 



Ichthyura brucei var. multuoma (Oregon and Washington). 



Pheosia diraidiata var. p()rtlandia (Oregon and Washington). 



Notodonta stragnla var. pacitica (California). 



Heterocampa guttivitta. Franconia, N. H. 



Cernra multiscripta. In the Northeastern States. 

 It should be noted that Cerura scitiscri2)ta is represented in New England by the dark forni> 

 C. multiscript((. 



It is greatly to be desired that hereafter collectors working in the Rocky 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 mouth), of their captures. 



Vll._0.\ THE PHYLOGEXY OR CLASSIFICATION OF THE LEPIDOPTERA. 



It hardly need be said that the classification of the Lepidoptera is in a very nnsatist\ictory 

 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 phylogeny 

 of the order is ditticnlt 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 



