A REVISION OF THE NORTH AMERICAN SPECIES OF
THE DIPTEROUS GENUS NEURIGONA.
(DOLICHOPODIDiE.)
M. C. Van Duzee.
The Dipterous genus Neurigona was established by Rondani
in Dipt. Ital. prodromus in 1856, with one species, quadrifasciata
Fabr., which is therefore the type of the genus. In 1829
Thomas Say described an American species as Medeterus
lateralis. Dr. Loew in 1864 pubhshed three others, dimidiata,
rubella, and tenuis, and in 1869 a fourth, carbonifer. In 1899
W. M. Wheeler added two more, floridida and lienosa, thus
giving us seven described species from America north of Mexico.
From farther south Prof. Aldrich has described decora and
signijer from Grenada and St. Vincent, and J. R. Schiner has
given us brasilie?tsis from Brazil. These are all the species
previously described from America so far as I can learn.
The genus Neurigona as characterized by Dr. Loew under
the name Saucropus in his Monograph of the Dolichopodidae of
North America are:
"First joint of the antennae without hair on the upper side; arista
dorsal ; thorax with a sloping area upon the middle of its posterior end ;
feet very long and slender; hind tibia? elongated, the first joint of hind
tarsi without bristles, shorter than the second; abdomen elongated and
narrow, especially in the male; hypopygium disengaged, short and stout,
inflected, with short very little developed appendages; color of the
body principally or at least partially yellow; hairs and bristles mostly
black. "
The above characters serve to define the genus as I use it in
the present paper but there are some exceptions that should be
noted. The bristles of the dorsum of the thorax are always
black, thus separating the species of this genus from those of
the genus Chrysotimus where they are yellow, but those of the
abdomen are often pale as are also the hairs especially in the
male. There is a group of western species which are entirely or
almost entirely blackish; the first joint of the hind tarsi is
sometimes longer than the second, as is the case in siiperbiens
Loew, which is synonymous with lateralis Say, and fully as
long in the male of tenuis Loew, also longer in australis n. sp.
In the table of genera of the Dolichopodidae in Williston's
Manual of the North American Diptera under No. 28 we have
to take fourth vein converging towards the third in order to
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