ECOLOGY OF ISLE ROYALE. 169 



from each other, and to be entitled to rank as a distinct species. In the fore- 

 going remarks reference only has been made to variations within specific limits. 

 The same law appears to hold between different species. In the genus Omus 

 the most roughly sculptured species occurs in Washington Territory, (0. Dejeanii 

 Reiche) and the smoothest (0. laevis, Horn) from near Visolia, California. The 

 object of the preceding remarks is to explain what appears to be a law of 

 variation for our western slope, and thus cause the unnecessary multiplication of 

 species, founded on slight characters, to be avoided. 



"Species everywhere in our fauna appear to be distributed on lines of country 

 presenting as nearly as possible similar meteorologic conditions. Thus many 

 Oregon forms extend southward into California, gradually seeking a higher 

 mountain habitat as the region becomes warmer. Two species illustrate this — 

 Tragosoma HarrisU and PTirygan-opMlus coUaris. Both extend their habitat 

 from Maine to California following the cooler regions westward from Maine 

 through the Canada and Red River region, thence northward nearly to Sitka. From 

 the latter point southward to Oregon both occur at ordinary level, and rising 

 as a more southern region is reached until at the latitude of Visalia they occur 

 only a short distance below the snow-line, at an altitude of from ten to twelve 

 thousand feet. p. 383. 



"As might be expected each new region visited yields new Meloidae of the 

 genera Epicauta and Lytta; in fact, each species of Astragalus has its peculiar 

 Lytta; and whenever any of that genus of plants is found in flower, an ac- 

 companying visitant may always be looked for." p. 384. 



LeConte, J. L. 1850. pp. 239-239*, 240*: "First, the entire absence^ [in Lake 

 Superior region] of all those groups which are peculiar to the American con- 

 tinent. Thus, there is no picaelus, no Pasimachus among the Carabica; the 

 Brachelytra are represented only by forms common to both continents. Among 

 the Buprestidae is no Brachys; in the Scarabaeidae, the American groups (except 

 Dichelonycha) are completely unrepresented; in brief, there is scarcely a genus 

 enumerated which has not its representative in the Old World, p. 239. 



"Secondly, the deficiency caused by the disappearance of characteristic forms, 

 is obviated by a large increase of the members of genera feebly represented 

 in the more temperate regions, and also by the introduction of many genera here- 

 tofore regarded as confined to the northern part of Europe and Asia. Among 

 these latter are many species which can be distinguished from their foreign 

 analogues only by the most careful examination, p. 239.* 



"When a species in one district is paralleled by another in a different region 

 so closely allied that upon a superficial glance they would be regarded as the 

 same. These are called analogous species; e. g., the Olisthaeri, Spondyli, Bem- 

 bidia, Helophori, etc., etc., of the preceding catalogue, as compared with European 

 species. 



"Where several species in one region are represented by several others of 

 the same genus, which perform a similar part in the economy of nature, without, 

 however, displaying any further affinity to each other. These are called equivalent 

 species; e. g., most of the species of Cicindela, Brachlnus, Clytus, Donacia, etc., 

 of America, as compared with those of the eastern world, p. 239.* 



"Notwithstanding this aDproximation to a uniform, subarctic star>d?rd, "^'.e still 

 find in these boreal regions, a prevailing character of North American fauna — 

 the extreme paucity of Curculionidae. The Donaciae too, although numerous, 

 do not afford any prominent parellelism." n, 240*. 



LeConte, J. L. 1851. pp. 249-250, 251, 252, 253-254. "The first fact observed 

 by the collector [in California], is the very small number of species which 

 can be obtained at any single locality. Day after day he meets with a continual 

 repetition of a few common forms, with an occasional admixture of rare species; 

 so that at the end of two or three months a single locality will have furnished 

 him with about 200 species of Coleoptera, and a rather less number of other 

 orders. It will be here remembered that the contrary is true of the eastern 

 part of the continent, where each locality furnishes a large number of species, 

 extending over a large area, and represented by comparatively few individuals. 



"On removing to another locality, the same thing is again observed, with this 

 difference:' the species of the first place, even the most abundant, are replaced 

 by others, many of which are true representative species, approaching as closely 

 as those of Eastern America and Europe; while others belong peculiarly to their 



