154 
PSYCHE 
[December 
SOME COMMON ERRORS IN THE NOMENCLATURE OF THE 
DIPTEROUS ^YING. 
BY S. W. WILLISTON, CHICAGO, ILL. 
There are in common u.se two systems of nomenclature for tlie dipterous venation 
at the present time. A third, that proposed by Comstock and Needham, ba.sed 
upon comparative studies, has, so far, not received much approbation among stu- 
dents of the order. 
The first and most commonly used of these systems is that given in detail by 
Ixiew in the first volume of the Monographs of North American Diptera; the second 
that adopted by Schiner in his later writings, and, since his time, by Wulp and 
Yerrall especially, as also several other recent writers. Neither of these was the 
creation of the writers. That given Iiy Loew was merely a codification of the usages 
of many of the early writers, especially IMeigen and ^^'iedemann, with some addi- 
tions and modifications propo.sed by himself. Schiner’s system, likewise, was a 
rehabilitation, with modifications and additions, of the usages of various writers, 
notably the English, with some terms of the earlier continental entomologists. Loew’s 
terminology was based chiefly upon the muscid venation, which he seemed to look 
upon as the more typical and primitive; he never attempted to apply his terminology 
to the nemocerous venation; in fact Loew never took enthusiastically to this division 
of the diptera. Sdiiner’s system also was more especially applied to the brachycerous 
and muscid types, though he did attempt to homologize it with the nemocerous 
venation. 
The application of neither sy.stem to the Nemocera has been altogether happy. 
Osten Sacken, when he came to use the Loewian nomenclature in the Tipulidae, 
was perplexed and led astray by some evident incongruities on Schiner’s part, and 
his example has done more than that of any one else to perpetuate some very jialpable 
errors, which, it seems to me, for the sake of consistency should be corrected — if either 
of these sy.stems is to be used. Comstock and Needham did better, and their 
homologies are, for the mo.st part, correct, I believe, though I am far from being 
assured that they have, in all ca.ses, reached the correct conclusions, or that future 
researches will not modify the interpretations they have accepted for some of the 
diptera. 
Schiner was the first to reach the conclusion that the ‘fourth’ longitudinal vein 
of the wing is the one which may be three-branched ; and that the fifth is two-branched 
