The Yellow Swarming Fly is one of the fruit fly family native to most of Europe, some of
North Africa and the Near East, Indo-Malaya and some of North America.
Several of these tiny yellow flies, about 2-3mm long, appear on my outside window on a sunny day in October and November.
They have bulbous, yellow abdomens.
Some appear to be blowing bubbles.
The top side of the abdomen has black, wasplike stripes and the thorax has less clear longditudinal stripes.
Mouthparts
Compound eye
This tiny black hammerhead fly was flying among the swarm one day, about the same size but obviously
a very different species, possibly a minute sawfly.