Fly

Despite its size this minuscule fly is a killer.

It's a tachenid fly, and they are parasite flies which prey on caterpillars, and other arthropods.  I'm kind of hoping it's cabbage whites, as there are rather too many of them around.

Anyway, for the inquiring mind here is (a lot) more info about these little insects.

Tachinidae is one of the largest families in order Diptera (at the present count 8,200 species with many many more to be discovered and described). Tachinid flies are relatively soft bodied, from small to large size insects. They may be drab, or brightly coloured, some are wasp-mimicking. Tachinid flies are extremely diverse in appearance and many do not have the typical grey-black, bristly faces.
 
All Tachinid Flies share the parasitoid habit. Their larvae are internal parasites of many orders and families of insects (and a few other arthropods). Their host ranges are relatively broad. They parasites on larvae of moths, larvae of butterflies, larvae and adults of beetles, adults of bugs, or adults of various orthopteroid orders, such as grasshoppers and stick insects. Depending on species, they develop either singly or in grope and either pupate in the dead host or leave the host and pupate in soil or plant litter.

Some Tachinid Flies are known to be host species-specific while some other species will use hosts in 2 or 3 different insect orders. Many Tachinid Flies are parasites of important pests of agricultural crops or forest trees. Some of them are used as parasitoids in integrated control programs. A small number of species have successfully been used as biological control agents. However, some Tachinid Flies are not always so obliging and many attempts at biological control using Tachinid Flies have failed. Instead of the target pest, the Tachinid Fly attacked some other unexpected targets.

We seem to be returning to the bad old days, when it took several attempts to get onto the site in the evening. Anyway, all I wanted to say was, don't forget Wide Angle Wednesday tomorrow. The subject is "interior". Please use the tag widwed08. Thanks.