Two Hoverflies

Hoverfly, Eristalis pertinax, on Cow Parsley, Anthriscus sylvestris, on Hillside Lane, Hayes. 13 June 2012.

Hoverflies are various and pretty, and I enjoy photographing them.  They like to visit flowers, which gives a sort of double photographic opportunity.

This one is a bee mimic, known as a Dronefly.  There are two native hoverflies that look like this, a warm brown abdomen with honey-coloured triangles at the side. The other one, Eristalis tenax,  has darker legs and distinct rows of hairs on its eyes.  Hairy eyes sound odd, but are no problem for insects.  If you look towards the ends of the wings you will see a vein with a wide loop; with one exception, this is specific to the tribe Eristalini, so it is a confirming characteristic.

This fly is a male.  All female hoverflies have a distinct gap between their large compound eyes.  This one only has a little triangle containing three much smaller eyes, the ocelli.

Hoverfly, Sphaerophoria scripta, on a Doves-foot Crane's-bill, Geranium molle, on West Wickham Common. 13 June 2012.

This hoverfly looks very different.  It's smaller and slimmer, and vividly marked.  There are several species that look very like this, and identification is usually not possible without collecting the creature and examining its genitalia, which I prefer not to do.  I like to leave them in the wild.

However ... this one, as you can see, is also a male, and in this one Sphaerophoria species, the abdomen of the male is markedly longer than the wings.