day by day poured out from countless chimneys, this moth "has during the last fifty years undergone a remarkable change. The white has entirely disappeared, and the wings have become totally black, so black that it has obtained the cognomen 'negro' from naturalists."[1] The dipterous insect Cœlopa frigida undergoes its transformations in the black sea-weed cast up by the spring tides. The flies and also the pupæ are black.[2] In a revision of the American orthopterous genus Spharageomon, Mr. Morse states: "Variation in colour in this genus, in common with other Œdipodinæ, counts for very little; the same species or race may be of all shades from a general dark fuscous to a pale buff or even a bright reddish brown, even in specimens from the same spot, yet it is probable that the general tint of a large series will be found to agree with the colour of the soil of the locality, or other peculiarity of environment. Specimens of different species from different localities in Colorado show a striking reddish almost rosaceous colouration due to some such cause."[3] Of course this can only apply to the insects when at rest, otherwise their more gaily-coloured under wings would contradict the view advocated. A. previous American writer, Mr. Brunner, had proposed that climatic differences had accounted for the varied colouration of the wings of some North American Locusts.[4] Eimer has some excellent observations on this point, and with these insects:—"The Grasshopper with red hinder wings banded with black, which is so common with us (in Germany) in summer, Acridium germanicum (Œdipodea germanica), when it occurs on the reddish brown Triassic clay of Tubingen, resembles this ground so closely with its wings folded that it cannot be distinguished from it. A little above the clay on the hills of this neighbourhood there occurs a whitish sandstone, sometimes only for the breadth of a path or in somewhat larger surfaces, frequently surrounded by the former. On these small patches of lighter ground I find regularly only Grasshoppers with quite light upper wings, so that they can scarcely be distinguished from the soil. And I have elsewhere observed the same remarkable
