240* LAKE SUPERIOR. 



and Ochthebius will afford other striking examples of this parallelism. 

 Among the Brachelytra are numerous other instances, the most re- 

 markable being the genus Olisthaerus, already alluded to. Protei- 

 nus and Megarthrus also for the first time appear on this continent. 

 The Aphodii with large scutellum, the Ditylus, Pytho, Sphaeriestes, 

 and Spondjlus are also good illustrations. Among the Elateridae are 

 numerous instances, but having not yet submitted this group to phi- 

 losophical study, I have not ventured to describe the new species, 

 but have merely indicated them by names. For the present there- 

 fore, any remarks on the parallelism of the forms in this group must 

 be postponed. Notwithstanding this approximation to a uniform, 

 subarctic standard, we still find in these boreal regions, a prevailing 

 character of North American fauna — the extreme paucity of Curcu- 

 lionidge. The Donaciae too, although numerous, do not afford any 

 prominent parallelism. The American species can only be regarded 

 as equivalent to the European. 



On concluding this short essay on the geographical distribution of 

 Coleoptera in the northern part of our continent, I feel that some 

 cause must be assigned for the brief manner in which such extensive 

 material has been disposed of. Enough has been given to point the 

 laws of distribution, and to show that they accord most perfectly with 

 those derived from other branches of natural history, while during 

 the yet imperfect condition of entomological science in this country, 

 a minute analysis of the components of the entire fauna would be a 

 work of immense labor, and would in fact be rendered nugatory, 

 until all the species are described, and all the groups submitted to a 

 philosophical revision. My complete success in tracing the par- 

 allelism between the Pselaphidae of Europe and North America (in 

 an unpublished monograph of this family) leads me to believe that 

 a rich store of material is herein presented to such minds as are satis- 

 fied with statistical comparisons between the inhabitants of different 

 zoological districts ; and that nothing but industry and a free access 

 to the most common European insects is required to produce a most 

 formidable list of analogous species. I shall rest satisfied with having 

 shown that this parallelism exists even more accurately than in the 

 vertebrate class, and with having pointed out examples far more 

 numerous than those furnished by the higher animals : the more so, 



