On catching 2 mm flies with a sweeping net

After about a year of intensive study of dipterans (i.e. flies, mosquitoes, midges and gnats), I've come to really appreciate collecting minute flies of 3 mm and smaller. After a careful observation using a dissecting microscope, I often end up looking at a fly rarely seen in France, each of them having less than twenty individual observations. These flies are not especially rare, most of them seem to be fairly common actually, but virtually nobody studies them. Citizen science platforms are great for larger or more colorful organisms, such as butterflies and beetles, but observing tiny dark flies is often a matter of specialists, which are usually really nice and helpful with my queries. I absolutely love spending a couple of hours on the tiniest black fly I found on dog feces outside, taking nice-enough macro-photographs and studying literature, just to feel buzzed and end up asking a 60-something years-old man I may find online who spent the last 40 years studying exactly this. One…