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Family Syrphidae — The Flower Flies 



Small to large flies, the wing with a "spurious vein"' lying between 

 the third and fourth longitudinal veins. 



Head variable, ])ut never elongated, except rarely the produced 

 epistoma. Face moderately wide to wide; eyes usually holoptie in the 

 males, always dichoptic in the females. Oral opening large; proboscis 

 usually short. Antenna? short or elongate, composed of three segments, 

 usually with a dorsal arista, rarely with a terminal style. Ocelli pres- 

 ent. Thorax rather large and robust, rarely with bristles. Abdomen 

 composed of four to six visible segments; hypopygium rarely promi- 

 nent, though often large. Legs variable but never elongate. Wings 

 comparatively large; third vein never branched, straight or dipped into 

 the apical cell, the apical cell closed; basal cells long; anal cell closed 

 before the margin of the wing, always long; between the third and 

 fourth veins a strong fold or ''spurious vein", rarely absent, which 

 is characteristic of the family. 



The Syrphidae comprise one of the largest and most popular groups 

 of Diptera. They may be found anywhere and many species are very 

 common. IMost of them visit flowers but some occur only in woods, in 

 moist places, in fields, or near ants' nests, depending upon their habits. 

 The adults display great variation in habitus but may be recognized 

 at once by their characteristic wing venation. Any locality with varied 

 habitat should yield at least a hundred species and the general collector 

 is certain to have many of them in his collection. Most of the common 

 species are easily recognized by the use of " Williston 's Synopsis" but 

 on the whole the family is a difficult one, many of the genera and 

 species being difficult to separate by means of keys and descriptions. 

 Unfortunately tliere is no recent revision of the North American forms 

 of which less than half are included in Williston 's w'ork. The number 

 of short papers dealing with the family is very large and the literature 

 scattered through numerous periodicals. ]\Iany attempts have been made 

 to divide the Syrphidge into subfamilies but with little success. Some of 

 the groups may be well defined in one region but almost every character 

 thus far used is found to lose its value when the study is extended to 

 include the world fauna. 



Almost all of the Syrphids are beneficial and they are second in 

 importance only to the bees as pollinators of plants. ]\Iany of them 

 live upon aphids, (plant lice) and mealy bugs in the larval stages. 

 A few are known to be definitely injurious. 



