Pregnant pause

Halteres are the vestigial hind wings of flies, and are believed to act as balance organs. I've never found an explanation as to why in Melanostoma scalare they're sometimes (though not always) green, but it's a peculiarity that as far as I'm aware only occurs in this species, so it can be useful for identification. Where the halteres are a more normal white or cream colour, M. scalare can be hard to separate from the very similar Melanostoma mellinum, but the face of a female M. mellinum looks more shiny and metallic than this. Both species are associated with grassland, but M. scalare is more tolerant of shade than its cousin, and is often found in gardens and woodland.

This female is clearly gravid with eggs. Her larvae will develop in grass tussocks or leaf litter, feeding (mainly at night) on small insects such as aphids.  Adults fly from March to November, in several generations with peaks in May and August, and visit a wide range of flowers and grasses, feeding on pollen and nectar. The final generation of the year overwinters at the larval stage, at the base of thick grass or in leaf litter.

R: C3, D6.