Notice the pairs of apical spines on the mid- and hind-tibiae...another diagnostic character for Sciaridae.

[Note: I've rotated the image here 180° so that the fly can be viewed in a more familiar orientation for study. But it was actually perched upside-down on the bottom of the flower sepal here (perhaps in wary response to my poking a large camera-lens-flash apparatus at it in the preceding minutes).]