PACKARD.] 



ZOOLOGY MOTHS OF COLORADO. 



545 



ains. The annual rain-fall of Fort Dalles, Orej?., is 22 inches, while 

 that of Nertchinsk, in the Altai Mountains, is 17 inches, that of Peking 

 being 24 inches ; so that the rain-fall of the elevated plateau ot Eastern 

 Asia and of Colorado is nearlj^ the same. Again, the annual rain-fall 

 of the Alps on their southern slopes is from GO to 90 inches 5 here we 

 have quite similar conditions to those of the Cascade range in Oregon. 

 These facts seem to explain the corresponding tacts in the variation 

 of the moths in the table given below. The warmer and more humid 

 Pacific slopes of America cause a more luxurious growth, a greater 

 development of the peripheral parts of the body, and slight changes in 

 coloration. The climatic conditions of the Rocky Mountains and Alps 

 being more alike than the White Mountains and Alps, we have certain 

 identical features in the variation of the alpine species of moths of those 

 two ranges of mountains which are not found in comparing White 

 Mountain and Labrador specimens with those from the Alps of Europe.* 





New England. 



Labrador. 



Colorado. 



Pacific coa.st. 



Pterophorns cinereidactylns . . . 



Wings shorter 

 Smaller 







Wings longer. 



Smaller 







Larger 



Larger. 

 Larger. 

 Larger. 

 Larger. 

 Larger and darker. 



Larger. 



Larger and paler. 





Smaller 



Stunted 



Smaller 



Smaller and 

 paler. 







Stunted 



Smaller 





Cidaria abrasaria | 











Camptogramma flnviata, 5 







Sm.aller 



Stunted and 

 darker. 



























Larger. 

















Larger 



Larger, with highly 

 colored yellow 

 hind-wings. 



Larger ; bleached . 



Larger. 



Laraer and highly 

 colored. 







Smaller, with 

 faded whitish 

 hind-wings. 



Smaller 









Smaller 



Larger. 











* Seven out of ten Colorado and Californian examples (length of fore-wing, cf , 0.62 inch) are consider- 

 ably larger than three eastern examples from New York and Maine (0.55 inch). 



t Three specimens from Iceland are darker than four from Labrador, and show great variation. 

 Labrador and White Mountain specimens the same. All are smaller than those fiom the Pacific coast. 

 In specimens from San Diego, Cal.. the wings are much broadrr than in Vancouver Lsland ones. Length 

 of fore-wing in three IceLind specimens, O.Gl inch ; four Lf.biador, 0.64 inch ; eight White Mountain, 

 0.64 inch ; three Vancouver Island, 0.70 inch ; two San Diego, 0.76 inch. This species varies much as 

 Macaria dispuncta. 



+ This speries also varies in the same way as Macaria dispuncta and Cidaria truncata. Two Lapland 

 individuals are much smaller and darker than two Labrador and one White Mountain ; and the latter 

 are smaller and slichtiy darker than seven from Vancouver Island. Length of fore-wing in largest 

 Lapland moth, 0.50 inch ; Labrador, 0.54 ; Vancouver Island, 0.04 inch. 



§ Five cf Californian examples (0.90 inch) are much larger than six from New England and Illinois, in 

 which the fore-wing in the largest specimen is 0.77 inch long. The Californian moths have the notches 

 and points much better marked on both pairs of wings than in eastern examples. 



II Tw(i Californian moths (0.80 inch) are a little larger than eight from the Atlantic States ; (length of 

 fore-wing, 0.88 inch). 



** On comparing 100 specimens, the California and Oregon examples measure thus : Length of longest 

 fore-wing, 0.97 i«ch ; of New England examples, 0.82 inch. 



It will be seen- from the facts here presented that the moths probably 

 follow, as regards size, a law the reverse of that established by Profes- 

 sor Bairdt for the birds and mammals, who shows that they decrease in 



" 111 tins connection we may state that it would bo veiy desirable to notice what 

 changes, if any, have been induced iu European species introduced by man into the 

 Moravian si-ttleiueiits of Labrador. 



i"The distriiiution and migrations of North American birds," Amer. Jonrn. Sc, 

 xii, Jan. and March, 18fi6. See also J. A. Alien, Bull. Mus. Conip. Zool., ii, 1871, " On in- 

 dividual and gengrai)liical variation among birds. &c. ; and R. llidgway, "On the rela- 

 tion between color and geographical distriljution in birds as exliibited in melauisru and 

 hyperchrumism," Amer. Journ. Sci., iv, Dec, 1872, p, 454; v. Jan., 1873, p. 3'J. 



35 OS 



