The species in the following list were taken in Fairmount Park during the past summer, and mainly during May and June, which is the best time for Syrphidæ; then there are some which only appear in the fall months. Of all families of Diptera the Syrphidæ seem to be better represented in the Park than any other families of this order, perhaps with the exception of the Dolichopodidæ. The Syrphidæ seem to prefer damp and somewhat open woods, especially a small wood that has a small rivulet running through, near the border, and where there are patches of May apple, with the sun shining through the trees on the plants. This only applies to some species, for others prefer the borders of woods, fields, etc. I never found many Syrphidæ in a hot and sandy county, for instance like New Jersey, but what it lacks in Syrphidæ it makes up with the Bombylidæ, for last summer I took about ten species of the latter family in one day, while I only took about seven species the whole summer in Fairmount Park.