The Society for the study of flies (Diptera)

Paul
Thank you for your prompt response.
I had considered L. caesar as the most likely, but I was not satisfied with an identification which was the most likely.
My problem was the weak bristles on the margin, as  the key allowed for strong bristles or no bristles. In future I will know to ignore weak bristles.
Again many thanks.

Howard
Can you give brief details of the two Melinda. I have just identified a Melinda, but on the basis of the keys took it no further than the one mentioned - M. gentilis.
I would very much like to get hold of the Rognes keys, but they seem not to be available at any price. I regularly search for them on the internet.

Sorry - I don't know what happened there. I'll try again.
The differences are subtle, and much of what follows (from the Rognes key) is qualified by that awful word "usually", so only make a definite decision when several characters coincide.

Both sexes: viridicyanea - presutural inra-alar present; palpi black: gentilis - prst ia absent; palpi (usually!) translucent brownish.

Males: viridicyanea - frons about as wide as third antennal segment, wider than posterior ocelli inclusive; erect hairing on tergites 3 and 4 much denser and finer dorsally than ventrally: gentilis - frons narrower on both criteria; hairing of tergites 3 and 4 much the same on both surfaces.

Females: viridicyanea - frons narrower than each eye; tergite 4 with discal setae (usually!); T6 in ovipositor (which needs to be pulled out) undusted all over: gentilis - frons about as wide as each eye; tergite 4 without discal setae; T6 conspicuously dusted on hind margin.

As usual, characters relying on measurement, such as frons width, are subject to wide and perhaps overlapping variation. I do find though that I can generally come to a conclusion about most individuals. I find the females easier - the T6 character is very clear once you get used to it. Occasionally there seems to be a mixture of characters, and I just have to give up.

Hope this helps.

Lucilia caesar males are also easily identified (even in the field) by the large genital capsule. You should be able to find both Melindas in Oxon, viridicyanea can be pretty common in grassland, scrub, post-industrial habitat, woodland rides etc. esp in more calcarous districts. Gentilis is a bit more localised. It looks a more robust in the field and males often cluster densely on sunlit foliage in woodland and scrub edge. They are both keyed out adequately in the RES tachinid/sarco'/calliph handbook by Van Emden, which hopefully is still available.

Falky