544 



GEOLOGICAL SUEVEY OF THE TEERITORIES. 



N. H., Jan., 1874, 244), and closely allied to Anarta melanopa and A. 

 Eichardsoni (A. algida), respectively. I should state that A. ^nelanopa^ 

 Tbunb., is recorded as occurring there on the authority of Mr. Grote. 

 All three species were collected by Mr. T. L. Mead in Colorado. It 

 should be borne in mind that the alpine fauna of Colorado also comprises 

 a few species not found in other alpine regions ; such are the two species 

 of Anarta and two of GMonohas (C. Chryocus and C. Uhleri, the former 

 occurring at Hudson's Bay). 



The following table shows the distribution of eight species of Fhalce- 

 nida}, which are found at an elevation of about 8,000 to 9,000 feet, 

 around the base of the mountains. They are subalpine and circum- 

 polar species, and also occur in the lowlands of north temperate America 

 and Europe. 





Colorado. 



Mount Wash- 

 ington. 



Labrador. 



Iceland. 



Alps. 



Lapland. 



Mountains 

 of Asia. 



Larentia csesiata 



Ciclaria populaia 



Cidaria lugubrata 



Cidaria testata 



Coremia ferrugata 



Melanippe hastata 



Melajiippe tristata 



Melanippe lugubrata . . . 



X 

 X 

 X 



X 

 X 



X 

 X 



X 

 X 



X 



X 



X 

 X 



X 

 X 



X 



X 

 X 



X 

 X 



X 

 X 



X 



X 



X 



X 

 X 



X 



X 



X 



X 

 X 

 X 

 X 

 X 



Cidaria testata and C. luguhrata will undoubtedly occur in the White 

 Mountains, as well as Melanippe luguhrata, since all except G. luguhrata 

 have been found in different parts of Northern New England. We are 

 also to look for Larentia dilutata (S. V.) in Colorado, as it occurs in New 

 England, and in Europe and Asia. From the facts here presented, it 

 will be seen how important it is to compare species occurring in nearly 

 identical isothermal lines around the globe, and to study the variations 

 in those species as occurring on opposite sides of the same continent, in 

 comparison with those on different continents. The facts offered in this 

 paper are exceedingly scanty, but yet indicate, so far as they go, some 

 interesting laws of climatic variation, which tend to confirm the generali- 

 zations established by Professor Baird and Mr. J. A. Allen, as regards 

 the avifauna of North America. I should, however, state that the fact 

 of variation in species common to both sides of our continent were forced 

 upon me by a study of the specimens themselves, without at the time 

 having the views of our ornithologists in mind. The species below be- 

 long to but four lepidoiDterous families, the FteropJioridce, Fhalcenidce, 

 Noctuidm, and Bomhycidce. In all those enumerated, as noticed more 

 fully in the remarks under each species, the Colorado (when the species 

 occurs there) and PacMc coast individuals are larger, and, in some cases, 

 with longer, more pointed wings, than in those from Labrador or New 

 England, and in a few species show a tendency to become lighter in 

 color. I believe that it will be found that these differences are due 

 almost solely to climatic causes. The climate of the Colorado Mount- 

 ains and of* Vancouver Island is much warmer than that of Northern New 

 England and Labrador. The mean annual temperature of Victoria, Van- 

 couver Island, is 50°, that of New York being the same; while that of 

 Labrador is 32O-30°. According to Professor G-uyot (Physical Geog- 

 raphy), the annual rain-fall of Astoria (about one hundred and twenty 

 miles south of Vancouver Island) is 86 inches, while that of Saint John's, 

 Newfoundland, is 63 inches (this is probably the same as the southern and 

 eastern coast of Labrador). The rain-fall of the Eocky Mountain region 

 is colored on Guyot's map the same as that of the Ural and Altai Mount- 



