OF WASHINGTON. 185 
The Circumpolar Fauna. There has been so much said and 
written on the circumpolar animals and plants, their origin, their 
movement southward during the Ice period, their retrograde move- 
ment at the end of that geological epoch, and the formation dur- 
ing this retrocession of more or less isolated colonies on very high 
mountain ranges; so many ingenious generalizations and specu- 
lations have been published by prominent botanists and zoolo- 
gists, that I am unable to add anything new on this subject. As 
to the Coleoptera of that region we have an admirable paper by 
Prof. Maklin, which, although written more than 30 years ago, is 
by no means antiquated, and a perusal of which is to be recom- 
mended to all interested in the matter. The southern limits of 
this fauna were laid down b}' Dr. LeConte, as early as 1859, 
on the map accompanying his paper on the Coleoptera of Kan- 
sas, and subsequent experience has found nothing to make great 
alterations. This limit is, of course, not a sharply defined line. 
The Arctic fauna gradually fades away, and south of this line many 
species occur of undoubted circumpolar origin, but which, in the 
course of time and under changed climatic conditions, have become 
specifically differentiated, either both in the New and Old Worlds or 
only in one of the two continents. These are what Maklin called 
the " representative species," and they form a large proportion of 
the fauna of our Middle and Western States. Other species have 
in their southward extent preserved their specific identity, and can 
then often not, or with difficulty, be distinguished from the im- 
ported species. Some of these have no doubt been reintroduced 
by the agency of man. 
In comparing the ranges of the circumpolar species in the Old 
and New World a striking difference is, in some instances, notice- 
able, which deserves especial mention and which is best explained 
by some examples : Lina lapponica of the family Chrysomelida, 
a variable but easily recognizable species which feeds on willow, 
occurs in all Arctic regions. In the Old World it occurs only in 
the 'high north and on high mountain ranges, whereas in North 
which exotic and American species were mixed and often without locality 
labels, the other specimen being still more doubtful regarding locality. 
These two specimens may or may not be from North America, but the in- 
teresting question regarding the time of introduction can never be 
answered with certainty. 
