Catharosia albisquama

Back at the end of Summer 2023, around the same time as Tachina magnicornis began to be found in East Suffolk, Ivan Perry spotted another new species in the same area – Catharosia albisquama.

Now, although the image above makes them look huge, it’s a miracle that Ivan ever spotted them, let alone guessed that they were tachinids, because they are absolutely minute – no more than 2-3mm in body length. He says he had been sweeping flowers and as he was pootering up a lot of small flies to study later he spotted these flies moving around in the net in a characteristic, tachinid-like way, so he took some home to check.

The way to split them from Catharosia pygmaea:

• Calyptrae blackish, wing scales somewhat lighter. Petiole of R5 1.5 – 2x as long as the post-angular vein (fig. 139). Propleura in front with 1 – 4 bristlets or hairs. Body length 2.5 – 4 mm … pygmaea Fall.
• Calyptrae and wing scales whitish. Petiole of R5 2 – 3x as long as the post-angular vein. Propleura bare. Body length 1.8 – 2.5 mm … albisquama Vill.