Some winter stems of sweet cicely, Osmorhiza sp., in my area are playing host right now to externally attached fly puparia. All of the puparia I've found so far have been attached in roughly the same place: the upper part of the stalk, below but close to where it first branches (puparium is the black spot on the stem in the first image of this series). Puparia may be reliably found by scrutinizing this area on the winter stems of sweet cicely in my area.

Close inspection suggests the puparia remain on the stem because they are formed just beneath the outermost layer of stem tissue -- suggesting this fly may mine the stem in its larval stage.

UPDATE, May 2017: I recently learned that the winter stems of honewort (Cryptotaenia canadensis) are very similar to those of sweet cicely, which made me wonder if some of the stems with puparia I originally collected might have been honewort. But since then I've learned to tell the stems apart and, after scrutinizing a number of stems of both species, I have found puparia on sweet cicely only. This leads me to believe the host for this fly is Osmorhiza specifically, but if I find any puparia on other stems I will add that information here.

Less dessicated adult from the same batch rearing here:


Stem miner