New families are now getting harder to find – I had high hopes from a batch caught during a work day lunchtime break with a fellow dipterist. He pointed out a mob of flies purposefully cruising back and forward over a stream, just out of net reach until the wind eddied slightly and brought them within striking distance. They sported unusually inflated front feet, but turned out to be Hilara, a genus of Empididae. Also promising was a fly with jauntily spotted wings swept from the edge of a bean field, but this was Trypeta zoe, a differently patterned Tephritid. Next, a greenish metallic fly swept from a buttercup-filled meadow was at first sight a hover fly, but seemed to lack the distinctive spurious vein of the Syrphidae. But all the other routes through the key ended up at families that were plainly wrong, and so eventually I concluded that it was Lejogaster metallina, a hover fly that can be confused with a soldier fly (Stratiomyidae); unfortunately for me this was the hover fly. My last hopes were pinned on a tiny fly also swept from the meadow that I thought might have been Drosophilidae, but my companion knew better, being an expert on the family. Of course he was right, and it turned out to be another Piophilidae.

Finding new families was becoming hard work, so it was somewhat of a relief when, as I was enjoying my breakfast outside, my toes dipped in clover, a distinctively purposeful and noisy fly joined me in the sunshine. As I got up to fetch my net it flitted away, but since we had both identified the sunniest and most sheltered spot in the garden, I suspected it might be back. With the net by my side I continued to contemplate the possibilities of the day. Half a cup of coffee later it landed on my net and with an expert flick of the wrist I curtailed its morning salutations. This was, without my needing to go through the key, a flesh fly of the family Sarcophagidae, as smartly turned out as a chap heading out to work in suit and tie. Its thorax was a neat pinstripe of grey and black stripes, set off nicely by gold dusting between the eyes, the abdomen tesselated in glinting black and grey, an eye-catching tweed.

I assumed that being such a large beast, taking the identification further would be trivial, possibly not even needing the microscope. I started off using my photocopied key (1954) to Calliphoridae by van Emden which includes what was then the subfamily Sarcophaginae. Finding the genus was a struggle through couplets asking if the hind coxae was setulose, about a row of inclinate frontal setae, and if the mid tibia had a postmedian ventral seta, but I cautiously arrived at Sarcophaga, for which the key noted: “The chaetotaxctic characters [ie. the bristles] are somewhat unreliable and the only way of obtaining quite definite identifications is by comparing the male genitalia.” With an updated version of the genus key I stumbled along, confirming that vein R1 was not setulose, that there were four presutural dorsocentrals, that abdominal tergite 3 had strong marginals – which brought me, possibly, to a choice of three widespread species, S. subvicina which is a parasite of earthworms, or one of a seemingly indistinguishable pair – S. carnaria and S. variegata – for which the first of which the van Emden key notes: “Larvae in decomposing organic matter, including dead animals, sometimes parasitic, even in man, causing intestinal myiasis etc.” The “etc.” was slightly worrying, as was the thought that worm or man, quick or dead, there was flesh fly for whom you were the right kind of food.