Collecting flies while they are mating is a surefire way to establish conspecific identity. Many female phorids are extremely different in appearance than the males (search this site for lots of examples), and linking the two together can be almost impossible, based on morphology.
In this case, we have a pair of Borgmeieriphora collected in a Malaise trap by Wendy Porras in Costa Rica. The females are wingless, reduced creatures, which however have a sharpened, parasitoid type ovipositor. They lived in army ant colonies, but are rarely collected. The only large series of specimens known is a group that I caught over such ants at La Selva Biological Station many years ago. The males were flying over the ants, carrying the females, as many phorids do. Since then, males have shown up frequently in trap samples, but until now females almost never. This new capture was surely a huge stroke of luck, because most mating pairs separate before they die in the alcohol.