Thaumatomyia notata

A tiny (2.5 mm) yellow fly with dark stripes on the thorax. Found in most habitats, most particularly from low bushes, woodland edges and waste ground. Can be common in gardens and may venture indoors when numbers build up later in the summer. There are several very similar species in the family so microscopic examination is needed. See the ID guidance below for the specific features to look for. Images in a pink box do not have the identification confirmed but are shown for illustrative purposes.

There are 5 UK Thaumatomyia species - all very similar. Chlorops are also very similar.

Thaumatomyia notata should have:

• wing length c2.1mm
• all yellow with 3 broad black stripes on the thorax
• the black triangle on the head is glossy with a row of hairs along each side
• scutellum covered in very short bristles
• arista without hairs (or nearly so)
• rounded face (frons not jutting forward)
• gena is narrow (much less than the width of the 1st antennal segment)

Mainly in flower meadows but sometimes it enters homes in large numbers and for this reason has been nicknamed Yellow Swarming Fly.

Spring and summer.

Larvae predaceous on aphids.

Widespread in England and Wales, but difficulties of species identification means that true status is uncertain.

Status in Leicestershire and Rutland is not known.