I noticed several syrphid flies ovipositing on the underside of a branch, directly above a small pool. Looking at the BugGuide images I think this is H. fasciatus. The flies (2 females, with at least one more individual hanging around) allowed me to get VERY close with my camera. Occasionally one or the other would fly down to the pool and perch on a leaf floating in it for ~10 s -- I believe they were drinking (or maybe just taking a breather from all that hard work!). It was fascinating to watch them lay the eggs one by one, in neat little rows!