ON PROPER GENERIC CONCEPTS. 
By CHARLES H. T. TOWNSEND. 
If any excuse be needed for presenting this subject, it is that 
we are face to face with the problem of adequate and practical 
generic concepts in the muscoid flies, and it is a patent fact 
that the soundness of our taxonomic system depends upon its 
correct solution. 
In approaching this problem it is important to review 
briefly the work of former systematists, in order to guard against 
a repetition of their errors. The genera of Meigen’s predeces- 
sors correspond roughly to our families and subfamilies, those 
of Meigen to our subfamilies and tribes. These authors do not, 
therefore, figure in this consideration. We may group subse- 
quent authors as specialists and generalists. 
Desvoidy was the first muscoid specialist. He had a close 
eye for differences, but often showed poor judgment in esti- 
mating the value of those differences. No one has ever accused 
him of confusing distinct forms under one name. His errors lay 
in attaching too great importance to minor characters subject 
to variation in the case of species, and in choosing insecure 
and invalid characters for some of his genera. 
Rondani was the next specialist in this group. Although 
in a sense a general dipterist, he possessed a very special know]l- 
edge of the Muscoidea. He, however, misidentified various 
species of the early authors, due perhaps in large measure 
to a revulsion of feeling prevailing in his time against the too 
minute and often misjudged discriminations of Desvoidy. 
With regard to genera, he revised and extended Desvoidy’s 
system, and his mistakes here are not conspicuous. 
Finally Brauer and Bergenstamm, and especially Brauer, 
abundantly won the honors as specialists in external muscoid 
characters, and they accomplished this by an intensive study of 
the external adult dnatomy, which led naturally to restricted 
genera and groups. The only blame that can attach to them is 
in their ignoring Desvoidy’s Myodaires and designating certain 
invalid genotypes. As intensive students of external characters, 
it is instructive to note how closely they approached the truth 
in the majority of their generic and group concepts. Those 
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