1873.] 17 [Packard. 



and in the subsaline [Insects 1 ] there are some close alliances with the 

 [insects] of the steppes of Siberia. And along the crests of high 

 mountain ranges the arctic-alpine [insect-fauna] has sent southward 

 more or less numerous representatives through the whole length of 

 the country " (p. 10). He then refers to the " astonishing similarity" 

 of the flora of the Atlantic United States with that of northeastern 

 Asia. Our actual knowledge of the insect species of northeastern 

 Asia is most vague compared with the exact knowledge of the botan- 

 ist, and the comparison we have drawn relates only to generic types. 



It is evident that the notion of continental bridges in quaternary 

 times, connecting, for example, Asia and California, is quite unneces- 

 sary, since there are, so far as is yet known, no forms characteristic of 

 Asia in the Californian fauna, and the grand difficult}- is to account for 

 the presence of a certain resemblance to the European fauna in that 

 of California. Here I think Dr. Gray has been the first to indicate a 

 solution of the problem. Our knowledge of American fossil tertiary 

 insects is at present almost nil ; we must, then, in the absence of any 

 evidence to the contrary, follow the conclusions of Gray with the 

 later confirmation of Lesquereux. 



The ancestors of the Californian Parnassius, RJiapJiidia, and other 

 European forms, may have inhabited the Arctic tertiary continent, 

 of which Greenland and Spitsbergen are the remains, and their de- 

 scendants forced southward have probably lost their foothold in the 

 Atlantic region, and survived in California and Europe, like the 

 Sequoia in California. Something more than similarity of climate is 

 needed to account for the similarity of generic forms; hence com- 

 munity of origin, with high antiquity and a southward migration of 



1 Dr. Leconte has noticed the similarity of our saline-plains beetles, containing 

 so many species of Tenebrionidae, to the fauna of the deserts and steppes of Asia. 

 (Proc. Amer. Assoc. Adv. Sci., 1851. Albany meeting, 252.) He also states that 

 " the only manner in which the insect fauna of California approaches that of Eu- 

 rope, is in the great abundance of apterous Tenebrionidae. But in this respect it 

 does not differ from a large part of South America; and by the very form of these 

 Tenebrionidae, which bear no resemblance at all to those of Europe, the greater 

 relation of the Californian fauna to that of the rest of America, is clearly proved." 

 Mr. Andrew Murray (On the Geographical Eelations of the chief Coleopterous 

 Faunae, p. 36, 1871) also refers to this fact; the genus Elodes in California replacing 

 the genus Blaps. He adds r " other Heteromerous forms, reminding us of Mediterra- 

 nean and Asiatic species, occur in California, and the whole of the northwest of 

 America has a greater preponderance of the microtypal stirps than perhaps occurs 

 east of the Rocky Mountains." I should add that Mr. Murray, in explaining the 

 term microtypal, states that " the fauna and flora of our own land [Great Britain] 

 may be taken as its type and standard." 



PROCEEDINGS B. S. N. H. — VOL. XVI. 2 NOVEMBER, 1873. 



