200 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Se*. 



spruce and barren wastes. North of the mountain is Jeffer- 

 son Park or Hanging Valley, set in the backbone of the Cas- 

 cades at an elevation of 5,400 to 6,000 feet. In ages past, 

 great glaciers moved down from the mountain and formed 

 this park, splitting as they advanced and going both east 

 and west; their remnants are still present on the sides of the 

 peak. The park is a series of beautiful clear lakes, clumps 

 of trees, and meadows. In the spring, the wild flowers car- 

 pet the mountain meadows and the insects, while not 

 abundant, are mostly uncommon forms, so that the collect- 

 ing there is fascinating. 



Oregon east of the Cascades is largely a plateau, broken 

 in the far east and south by mountain ranges and low rocky 

 hills. There are many fertile valleys, but much of the region 

 is arid. The elevation averages 4,000 feet. Scarcely any 

 collecting has been done in the Blue Mountains country or 

 in the southeast where there are many lakes and small 

 streams. 



DISTRIBUTION 



Collectors in the past have noted the fact that diptera 

 from the western United States resemble those of Europe 

 more closely than do the species in the eastern part of the 

 country, there being many cases of specific identity. Osten 

 Sacken discussed this resemblence at length in his "Western 

 Diptera." The Trichoceras are not so rare in California 

 as Osten Sacken was led to think from his limited collecting, 

 and in Oregon they are very abundant in the winter and 

 early spring. The genus Villa (Anthrax) is not so well rep- 

 resented in Oregon as farther south, but the asilid genus 

 Cyrtopogon is rich in species, many of the forms appearing 

 to be limited to the Lower Boreal zone. The western syrphid 

 genera Arctophila, Pocota and Pyritis are typically north- 

 western forms, and there are many species of Chilosia and 

 Pipiza in this area. Two species of the cyrtid genus 

 Eulonchus are not uncommon in parts of Oregon, but the 

 two other known species in the genus are probably more 

 southern in their range. The Blepharoceridae are typically 

 western diptera and are remarkably abundant in the Hood 

 River valley of Oregon. The western fauna as a whole is 

 limited to the line of summer dryness in its spread to the 



