The eyes have it

At the request of the parish council I have, for about a month now, been recording insects and other arthropods from a scruffy and neglected patch of ground adjacent to Byfield Pocket Park. As one might expect, the species recorded have been mundane and rather predictable. But a couple of days ago I recorded my first surprise.


Stomorhina lunata is known as the Locust Blowfly. It is related to blowflies and in warmer climates is known to be a predator on the eggs pods of locusts and large grasshoppers. It is tempting to believe that it preys on British grasshoppers in a similar manner but there seems no evidence that this is the case.

The Locust Blowfly has turned up in Byfield Pocket Park

With its striped eyes and rather long 'snout' it is a striking insect and I had never previously found a specimen. It is a 'first' for Northamptonshire.

Also striking, and found nearby a few minutes later, was Coreomacera marginata. The name Sieve-winged Snailkiller has been coined for this and is, I suppose, reasonably appropriate. It is a member of the Sciomyzidae, a family of snail-killing flies. It will be seen that this species also has striped eyes even though this, and the Locust blowfly are only distantly related.




Coremacera marginata was also present in the pocket park.

Photograph: Jessica Joachim

Eyes with this kind of banding are to be found in several groups of diptera (two-winged flies) with several clegs (species of Haematopota). Of course, as a rule people seeing one of these on their body quickly slap them before they bite! The Notch-horned Cleg, Haematopota pluvialis, has also been recorded from this site. The species is all-too common.

Many a country walker has received a bite from Haematopota pluvialis

Eristalinus sepulchralis is rather different, having spotted rather than banded eyes. I find it occasionally, usually in damp areas, but it is not particularly common and has not been found at the Byfield site.

Eristalinus sepulchralis is from yet another family. It is a hoverfly and

therefore a member of the Syrphidae

As for Eristalinus taeniops, the Band-eyed Drone fly, I have never found it - nor am I likely to now although it does occur in Mediterranean countries.

Eristalis taeniops has a wide range, but has not reached Britain.

In recent years a number of flies have been moving northwards, a situation generally ascribed to climate change. This is what has happened with Stomorhina lunata, the fly with which I started this blog. So the Band-eyed Drone Fly could make an appearance...but I won't hold my breath.