82 ' FIELD AND FOREST. 



plete data regarding variation in color should be collated before the 

 facts can be regarded as establishing any conclusive law of melanism. 



Although I have not had an opportunity to institute extensive com- 

 parisons between collections from different mountain regions ; obser- 

 vations made in the west, during several seasons, have convinced me 

 that in general the animal kingdom existing at great elevations is as 

 dwarfish as the vegetable kingdom. 



This is especially apparent in the Coleoptera, Hemiptera, Orthoptera, 

 Neuroptera and Arachnida, the types of which are usually represented 

 by the smaller species. But this does not appear to be the case with 

 the Lepidoptera, Hymenoptera and Diptera ; which furnish large sized 

 forms, especially prominent, among which are the Papilionid(z, Ar- 

 gynnides, ApidcB Tabanidce. 



The Southern Rocky Mountain chain appears to support a greater 

 abundance of some orders of insects than the Northern. A seasons' col- 

 lecting above timber line in northern Colorado, only produced five spe- 

 cies of butterflies, while the mountains of New Mexico yielded sixteen 

 species. 



The ratio of luxuriance, however, in the case of some other orders is 

 largely in favor of the northern mountains ; a result seemingly incon- 

 gruous, but which undoubtedly bears directly upon the biology of each 

 order of insects. Of all orders the Lepidoptera is the one Avhich most 

 delights in a warm climate and bright sunshine, and any deviation 

 from such an habit should be regarded as an involuntary change ren- 

 dered obligatory by the slow substitution of a cold climate during 

 ages of progress in their developement. 



The temperature of the climate of the mountains of New Mexico is 

 considerably warmer than that of the same elevation in Colorado ; the 

 alpine flora consequently extends into higher regions in New Mexico, 

 making a suitable habitat for the Lepidoptera. Hemiptera and Diptera, 

 three of the most delicate orders of insects. The Coleoptera, LLymefi- 

 optera, Orthoptera, Araehnida and Myriopoda being more hardy, ac- 

 cordingly predominate in more northern regions. 



In the collection made by myself last season in New Mexico and 

 Colorado at an elevation exceeding 12,000 feet above the sea, there 

 were 17 species of butterflies, 4 of moths, 7 of ILyinenoptera, 30 of 

 Coleoptera, 10 of LLemiptera, 5 of Orthoptera, 5 of Araneiiia, i of 

 Myriopoda and 2 of Land Shells. Of this collection nearly one half 



