6 DURHAM DIPTERA 



EXPLANATION OF THE NUMBERING. 



In the Index of the description of the Fly Chart, that is the 

 explanation of terms and parts, the Capital letter refers to 

 the division so lettered in that description, the Roman numeral 

 to the section of that division, and the Arabic numeral to 

 the paragraph of the given section, except where the capital 

 letter is V, O, or X, which refers to the list of wing names. 



In the Tables of Families, Genera and Species, a Roman 

 Numeral, followed by a light Arabic Numeral in brackets, 

 refers to the plates of illustrations. Thus (VI., i) means 

 that an illustration of the foregoing description will be found 

 at No. i of Plate VI. 



The Families, Genera, and Species follow the order of Mr. 

 Verrall's list issued 1901, although with many omissions. 

 The Families, all of which end in idee, are numbered in Roman 

 numerals, I-LX. The Genera are numbered straight through 

 as placed in the list, in Black Arabic numerals 1-672. The 

 Species are also numbered straight through in the same 

 manner in Light Arabic numerals 1-2884, s0 as to indicate 

 their proper order, and to point out omissions. 



At the top of each page is the number of the family and 

 genus with which the page begins, or, if it be a table of 

 genera, then only the family number. Thus, suppose Tanypus 

 nervosus were the first species on the page, then VI. 80 would 

 stand as the page number, Tanypus being the 80th genus 

 and Chironomidae the 6th family in Verrall's list. 



In using the tables, having found the family, pass on 

 to the beginning of the pages bearing that family's Roman 

 numeral, where the table of genera will be found, and having 

 found the genus pass on to the first of the pages with the 

 dark Arabic numeral of the genus, or the nearest lower 

 number, where the table of species will be found. 



If the number of a family, genus, or species precede its 

 name, it indicates a stop : there are no further particulars 

 given. If the number follow its name it indicates : pass on 



