1124 
DIPTERA OF AUSTRALIA, 
would be made much move difficult, or it would necessitate 
forming numerous sub-sections whereby to define the peculiarities 
of several series of species haviug details of structure in common. 
Insufficiently characterised genera cause much difficulty, particu- 
larly when the type-specimens are not at hand for reference ; and 
a glance at the synonymy will show to what a lamentable extent 
worthless genera encumber our classification ; on the other 
liand, a genus established which at once sums up the joint 
characters of the species which belong to it, or which serves as 
an index to one or more species, cannot fail to be of service to 
the study of such a multitudinous order of insects as the Diptera, 
whose identity of structure in certain families and sub-families is 
maintained to such a puzzling degree. Much confusion has been 
perpetrated by the manner in which some authors have ignored 
minor details in structure — minor in comparative magnitude, but 
important in significance ; for instance, the sub-costal cross-vein, 
auxiliary vein, and the exact position of other veins, to which 
Winnertz, in his masterly work on the JNIycetophilidae, attaches 
much importance, hav’e been so unimportant in the opinion of 
some writers that not only is their mention quite omitted, but 
they are wanting in the figures employed ostensibly to illustrate 
the alar-vein system so essential to notice in a newly-described 
generic or sj)ecific form. 
The species upon which new generic names have not been con- 
ferred, added to those delineated by Walker, belong to the following 
genera : — Macrocera (3), Cerojylatus (1), Platyura (8), Sciojyhila (1), 
Leia (1), Trichonta (2), and Mycetophila (2), though, as can be 
readily seen, it is more than probable that those of Walker will 
be extremely difficult to determine from his poor descriptions ; as 
to the localities of the latter, thi’ee are stated to be from “ Van 
Diemen’s Land ” and the fourth from the very vague locality 
“ New Holland.” 
I think that an investigation of the genital organs of the male 
would result in very interesting and valuable additions to our 
knowledge of the Mycetophilidae, and the characters and struc- 
ture of these would perhaps prove useful in defining the genera. 
