216 Wisconsin Academy of Sciences, Arts, and Letters. 
plenty to learn, specially in snch difficult groups as Syrphus, 
Platychirus, and Helophilus. I have tried to make the keys sim¬ 
ple enough for the average entomological student to identify the 
species in his collection. In 1910 Dr. Graenicher published a 
list of 92 species for the state; the present list contains 137, 
which indicates the richness of Wisconsin’s fauna. 
I am indebted to the members of the Department of Economic 
Entomology of the University of Wisconsin for numerous speci¬ 
mens ; to Professor H. P. Wilson for his encouragement and for 
many helps in securing literature; to Dr. Graenicher and Profes¬ 
sor T. E. B. Pope for permission to study the specimens in the 
Milwaukee Public Museum, and to Dr. W. S. Marshall for his 
kindness in showing me many references and permitting me to 
study his collection. To all these I am most heartily grateful. 
Characteristics of the Family 
“ Small to rather large flies. Head hemispherical, often elon¬ 
gated or produced in the lower part; as broad or a little broader 
than the thorax. Face moderately broad, bare or clothed with 
dust or short pile; excavated in profile under the antennae and 
projecting below, or with a distinct convexity near the middle 
part, never with longitudinal furrows or lateral ridges, usually 
convex transversely, sometimes with a median ridge. Oral open¬ 
ing large; proboscis rarely much elongated. Front never exca¬ 
vated. Antennae usually porrect and approximated at their 
base, three-jointed, usually with a dorsal arista. Eyes large, 
bare or pilose; in the male usually contiguous above. Ocelli al¬ 
ways present. Thorax comparatively large and robust, moder¬ 
ately arched above. Squamae of moderate size. Abdomen com¬ 
posed of five or six visible segments, rarely with only four. 
Hypopygium usually not prominent. Legs usually of moderate 
strength, never long. Bristles rarely present in any part of the 
body, never on the head; the body generally thinly pilose or 
bare, but sometimes clothed with thick pile. Wings compara¬ 
tively large; third longitudinal vein never forked; marginal cell 
open or closed; the fourth vein terminates in the third at or 
before its tip; three posterior cells; basal cells large; anal cell 
always closed before the border of the wing; between the third 
and fourth longitudinal vein and nearly parallel with them, a 
false or spurious vein, nearly always present and characteristic of 
the family. ’ Williston. 
