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 Sacken, 

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

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

 inidae and Dexiidae, are unknown to the writer. 



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

 for the family characters and table of the Dolichopodida ; 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 Ortalidae. 



Lawrknce, Kans., June 10, 1890. 



C () R R I G E N D A . 

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



V X, line 10, for 'lieinisplierifal' read spherical. 

 »<xix, line 5 from bottom, for 'Cyclorrhaplia' read Ortliorrliapha. 

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



the following line. 

 " 81, line 4 from bottom, for 'anal eell closed' read discal cell open. 

 ^ 82, line 2, for 'Thambeta Williston' read Diotiiepha Osten Sacken. 

 * 35, line 14, for '5' read 8. 

 *^40, line 18 from bottom, insert flattened before 'cylindrical', and, 



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

 •^ 48, last line, for 'SubulaOmvia, nom. nov.' read Xyi.omvia Rondani. 

 voS^.Tine 18, for 'Ortiioneuromyia Williston' read Psii.ocurus Loew. 

 \^88, line 17 from bottom, for '04' read 07 ; line from bottom for '07' 



read (if). 

 ^ 00, line lo from bottom, for 'Euniyidae' read Holometopa ; line 11 



from bottom, for 'Schizophora' read Eumyida;. 

 y 140, line 8, for 'with' rea<l without. 



