202 CALIFORNIA ACADEMY OF SCIENCES [Phoc. 4th Sex. 



The Hudsonian zone is narrowed in Oregon and follows 

 down the Cascades into the Sierra of California, ascending 

 as it goes south, until in southern California it is limited to a 

 few mountain peaks. The zones of eastern Oregon have not 

 been carefully worked out, but there are a number of moun- 

 tains extending up into the Canadian and Hudsonian zones. 

 A great many records will be added to the diptera list when 

 this region is worked over. Many of the typical Californian 

 zone species are not found in Oregon as far as our collecting 

 shows, but we have obtained some of these forms and more 

 will be found in the southern part of the state. The Van- 

 couveran and Pacific Maritime zones are rich in species of 

 Mycetophilidse, many of which are undescribed. 



ACKNOWLEDGMENTS 



The general arrangement of this list was planned by both 

 authors. Prof. Lovett has written up the Syrphida; and we 

 are indebted to Mr. Leroy Childs for much of the work on 

 the Tabanidae and for material collected at Hood River. The 

 senior author is responsible for the work on the other fami- 

 lies of diptera, except where material was turned over to 

 specialists in some of the groups, and for the drawings illus- 

 trating most of the families represented. 



Several dipterists have been of help to us in determining 

 material in families in which they are specializing, and to the 

 following we wish to express our thanks: Mr. J. R. Mal- 

 loch, Dr. C. P. Alexander, Mr. M. C. Van Duzee, Dr. J. M. 

 Aldrich, Prof. J. S. Hine, Dr. A. L. Melander, Mr. A. 

 Spuler, Dr. E. P. Felt, Prof. R. C. Osburn, Mr. E. T. Cres- 

 son, Jr., and Mr. C. H. Curran. We are also indebted to 

 the entomologists at the Oregon Agricultural College for 

 specimens they have collected and to the following members 

 of the staff of the Forest Grove Experiment Station, Bureau 

 of Entomology, U. S. Department of Agriculture : Mr. M. 

 C. Lane, Mr. L. P. Rockwood, Mr. J. B. Thompson, Mr. 

 A. C. Burrill, Mr. C. W. Creel, and Mr. M. M. Reeher. 

 Mr. E. P. Van Duzee has added several records from south- 

 ern Oregon which were particularly valuable because we 

 know so little of the diptera in that region. 



