PREFACE 



The publication of Kertesz's " Katalog der Palaarktischen Dipteren," 

 Band II. 1903, has rendered it unnecessary to give detailed bibliographical 

 references to the species included in this List. 



An endeavour has however been made to arrange the species in 

 systematic order, and although this is probably far from being accurate 

 yet it may draw the attention of students to allied species and thereby 

 facilitate nomenclature. An attempt has sometimes been made to indicate 

 groups of species by means of dotted lines, and the number of dots roughly 

 indicates the distinctness of the groups. 



Many changes in synonymy have been introduced, but in no case 

 without good reason. 



