NO. 15 



SMITHSONIAN EXPLORATIONS, 1 92 1 



61 



Mount Rainier, and in less degree, to other mountains of the Pacific 

 northwest. The relation of this element to the Asiatic fauna is very 

 little known. 



The third element of the Alaska fauna, as far as observed, is that 

 of the dry interior and especially of the Yukon Valley, which has 

 many elements in common with Northern Minnesota, Wisconsin and 

 Michigan, Ontario, the Adirondack Mountains of New York and the 

 White Mountains of New Hampshire. Many of the insects of this 

 group also occur in the Rocky Mountains of Colorado and no doubt 

 further exploration will show that they occur in other mountains 

 of the western United States. Those which represent a more northern 



Fig. 66. — Town of Healy in the lignite belt on the Nenana Ri\ cr. Alaska. 



range also reappear in Labrador collections, and presumably extend 

 across North America although we have no collections from inter- 

 mediate points. This element contains many species known from 

 Finland and the Scandinavian Peninsula in Europe, presumably ex- 

 tending in their distribution across Russia and Siberia. 



In most orders of insects Alaska has a comparatively large fauna. 

 There are very numerous species of the two-winged fiies, or Diptera ; 

 and from Doctor Aldrich's long experience with this group he natur- 

 ally paid especial attention to collecting in this order. Bumble bees 

 and wasps are conspicuous insects everywhere on flowers ; and in the 

 absence of darkness bumble bees were observed to work as late as 

 10.30 at night in Fairbanks. Grasshoppers were strikingly scarce, 

 only two species being found and in all but half a dozen specimens. 



