SYRPHIDAE OF WISCONSIN 
CHARLES L. FLUKE, JR. 
The predaceous forms of Syrphidae have seldom received the 
credit which is due them for their share in the suppression of the 
endless increase of individuals in colonies of plant lice. Hereto¬ 
fore whenever the enemies of aphids were mentioned the lady 
beetles usually took first place, and oftentimes the syrphus flies 
were not even mentioned. 
Today the entomologist and even many others are beginning 
to realize the true value of Syrphidae as plant-lice predators. 
Instead of being placed at the bottom of the list, they are now 
treated as the most important factors in the checking of unusual 
outbreaks of plant lice. Most aphidologists are now recognizing 
this fact. A large part of this is due to education along this 
line; and the life-history studies of these forms as carried on by 
such men as Metcalf have been a great factor in the enlighten¬ 
ment received regarding these most interesting creatures. 
The European grain louse has never been a destructive pest 
to apple trees in Wisconsin. This spring (1920), as in many 
others past, the young lice hatched in countless numbers and 
soon began to multiply. From all appearances spraying would 
be necessary to reduce their numbers. A careful examination 
of the opening buds showed, almost without exception, one to 
several syrphid eggs placed among the plant lice on each grow¬ 
ing tip. Repeated observations soon made evident the reason 
of the non-destructiveness of the aphids. The syrphid larvae 
preyed upon the plant lice with such voraciousness that few sur¬ 
vived to migrate to their summer hosts. 
For several seasons biological notes of many of the common 
species occurring in Wisconsin have been gathered. It has been 
decided to give only a classification of the adults at this time, 
with the intention of publishing later the life-history observa¬ 
tions. 
The Syrphidae have been intensively studied but there is still 
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