SOME AMERICAN SYRPHID FLIES 
By Frank M. Hull 
University of Mississippi 
Recent collections of flies submitted to the author con- 
tain a number of neotropical species of Baccha which are 
undescribed. This paper gives the descriptions of these 
flies. A species of Rhinoprosopa is included. 
Baccha balboa n. sp. 
A petiolate species, the face without tubercle, the an- 
terior margin of the wing narrowly brown. Related to 
bigoti Austen but without the reddish spots on the fourth 
segment and with different pattern upon the wing. 
Length 10 mm. 
Male. Head: the vertex is polished black, rather flat, 
the long black pile lies in a single row. The front is 
black, with faint bluish reflections and protuberant just 
in front of the narrow antennal callus; the sides of the 
front are diffusely yellowish grey pollinose; the frontal 
pile is long and fine and black. The face is black with 
faint bluish reflections, nearly straight in profile but 
retreating and without tubercle; the sides are widely 
yellowish grey pubescent with similarly colored pile. 
The antennae are dark brown, the third segment and apex 
of the second segment reddish below ; arista dark brown. 
The occiput is yellowish grey pollinose with fine, white, 
non-scalose pile which becomes blackish near the vertex. 
The posterior eye margin is not indented in the middle 
but the eye is developed above so that the occiput can not 
be seen laterally on the upper third. Thorax: the meso- 
notum is polished shining including the scutellum; the 
humeri and the post calli are shining, dark sepia brown; 
there are no vittae present and no pollen. The mesonotal 
pile is fine, erect, fairly long and blackish without anterior 
collar, the pile becoming shorter and pale yellow in front 
of the scutellum. The scutellar pile is fine and long and 
yellow ; the ventral fringe consists of fifteen or more pairs 
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