THE CANADIAN ENTOMOLOGIST. 315 



The Fungus Gnats of North America. By Oskar A. Johannsen, 

 Ph.D. Parts I-IV, from Bulletins 172, 180, 196 and 200. Maine 

 Agricultural Experiment Station, Orono, Me. 



The concluding part of this admirable work was issued in June of the 

 present year, the first part having appeared in Dec, 1909, and the second 

 and third parts in June, 19 10, and Dec, 19 11, respectively. It is a work 

 of 306 pages, whose aim is to "present a synopsis of the fungus gnats, or 

 Mycetophilidae, of North America, giving descriptions of and tables to all 

 the genera and species and life-histories when known." On account of 

 their small size and unattractive appearance, these flies have hitherto 

 received little attention from systematic entomologists, so that the prepar- 

 ation of the keys and descriptions of the 82 genera and 428 species must 

 have been a task of unusual difiiculty, demanding an exceptional amount 

 of patience and industry on the part of the author, who is therefore the 

 more to be congratulated upon his having so successfully accom- 

 plished it. 



In the first part the general characters of the family in their various 

 stages are discussed, special attention being given to the venation and the 

 form of the hypopygium of the male. There is also a short discussion of the 

 habits and economic relations of the groups as a whole and an analytical 

 key to the eight subfamilies. The remainder of Part I is devoted to the 

 systematic treatment of the first five subfamilies (Bolitophilinae, 

 Mycetobiinae, Diadocidiinse, Ceroplatinje and Macrocerinae), all of which 

 are comparatively small groups. Fifteen genera and 71 species, of 

 which 1 1 are new, are described in this part. 



Part II deals with the Sciophilinae, and includes a short account of 

 their habits and earlier stages, in addition to the tables and descriptions. 

 Twenty-nine of the 69 species described in this part are new, most of these 

 belonging to the two largest genera, Sciophila and Mycomya. 



Parts III and IV treat of the Mycetophilinae and Sciarinse, the two 

 groups of the most economic importance. The former is the largest of 

 the subfamilies, embracing 48 genera and no species, of which 54 are 

 described as new. In the Sciarinae 9 genera and 56 species are described, 

 46 of the latter belong to Sciara, including 22 new species. 



