IV PREFACE. 



Diptera ever brought together. For the descriptions of the 

 early stages reliance has necessarily been placed chiefly upon 

 the writings of Brauer. As will be seen, assistance has 

 been derived from the works of Schiner, Osten Sackeri, 

 Loew, Wulp, Townsend and others, although but very few 

 of the North American genera, aside from those of the Tach- 

 inidae and Dexiidse, are unknown to the writer. 



The author owes his sincerest thanks to Prof. J. M. Aldrich 

 for the family characters and table of the Dolichopodidae ; to 

 Prof. V. L. Kellogg for the paragraphs on the internal anat- 

 omy of Diptera ; to Prof. J. B. Smith for kind favors ; and to 

 Prof. W. A. Snow for the table of the Ortalidse. 



LAWRENCE, KANS., June 10, 1896. 



CORRIGENDA. 

 Page viii, line 9, for 'writer' read student. 



x, line 10, for 'hemispherical' read spherical. 

 xix, line 5 from bottom, for 'Cyclorrhapha' read Orthorrhapha. 

 18, line 2 from bottom, insert not before 'forked' and delete from 

 the following line. 



31, line 4 from bottom, for 'anal cell closed' read discal cell open. 



32, line 2, for 'THAMBETA Williston' read DIOTREPHA Osten Sacken. 

 35, line 14, for '5' read 3. 



40, line 13 from bottom, insert flattened before 'cylindrical', and, 

 three lines below, read 'tibiae with or without spurs.' 



43, last line, for 'SUBULA OMYIA, nom, nov.' read XYLOMVIA Rondani. 



58. line 13, for 'ORTHONEUROMYIA Williston' read PSILOCURDS Loew. 



88, line 17 from bottom, for '64' read 67 ; line 6 from bottom for '67' 

 read 65. 



96, line 15 from bottom, for 'Eumyidae' read Holometopa ; line 11 



from bottom, for 'Schizophora' read Eumridte. 

 140, line 3, for 'with' read without. 



