DISTRIBUTE INSECT VARIETY. 291 



Loricera piUcornis, naturally brassy, becomes somewhat ferru- 

 ginous. We have likewise the dark Highland forms of Carahis 

 cantenulatm and the mountain Nabigena. Then, as regards 

 Europe, Car.ahus clathratus in the south is large and able to fly ; 

 in Sweden and Siberia it is small and can only creep on the 

 ground. The Long-horned Beetle, Saperda scalaris, frequenting 

 poplars, in Lapland is covered with an ashy white instead of 

 yellow pile. Coleoptera from the Alps, Pyrenees, and Apennines 

 are also often dwarfed, and a variation of altitude obscures the 

 colours of Alpine beetles, whether terrestrial, floral, stercoraceous, 

 or aqueous, so that species in the inferior zones ornate with 

 colours of metallic reflection become on the elevation uniformly 

 black. Those green and coppery in the high Alps are pure black, 

 while a smaller number steel-blue and deep blue, with others 

 brown, olive, and golden green, pass into pure or bluish black. 

 Even the yellow leaf-feeding Chr^somela alpina becomes black. 

 Carahis Rossi, Dej., for like reasons, is dwarfed in the Apennines, 

 and there assumes a chestnut-browai hue ; and our common South 

 of England scavenger Carahus violaceiis, Lin., dwarfed and 

 blackish in the Tyrol, in Central Italy is large, with violet elytra 

 margined with golden. This melanism and dwarfing is, as in 

 other cases, ascribed to a prolongation of the metamorphosis, 

 passed often beneath the rnountain snow. Proximity to the sea- 

 coast likewise dwarfs beetles and afliects their coloration. For 

 example, I have observed the Coleoptera of Calais on the French 

 coast are often smaller than those taken at Lille ; so PimeJa 

 Fairmarei at Morocco attains but half the dimensions it takes 

 farther inland. 



As regards insular varieties, the Isle of Man, according to Mr. 

 Rye, furnishes a dwarf form of the common Oil Beetle, and exem- 

 plifies an intensifying in the colour and punctuation of certain 

 of the smaller terrestrial beetles. The Coleoptera of the Shetland 

 Islands are alleged to be dark and dwarfed. On small oceanic 

 islands that give us the Dodo and Solitaire, the insect fauna is 

 likewise often apterous, as has been observed by the Rev. Mr. 

 Eaton in Kerguelen's Island, and by Mr. Wollaston in Madeira. 

 On the latter outlier of the European plant and animal life, two 

 in every five of the beetle species proved so far deficient in 

 wings that they could not fly — a peculiarity Dr. Darwin attri- 

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