Opesia grandis

This is another of Ivan Perry’s discoveries and is really rather exciting – a bit more than your average ‘new to the UK’ species because it is incredibly rare even in mainland Europe too. The species seems to be commonest in Eastern Europe but wherever it occurs it is very rare … Peter Tschorsnig (the foremost European tachinid expert) had records for about 25 in the whole of Europe!

There are no common members of the genus Opesia but, just in case you stumble upon on, grandis will key to Opesia cana in Belshaw so modify it thus:

1. Thorax before the suture with three black middle stripes (in males often merged, in females, the central stripe is sometimes only faintly visible).  Basicosta black-brown, like tegula. Calyptrae white (males) or faintly yellowish (females). Two katepisternal (= sternopleural) bristles (seldom 3, very seldom 1). Frontal bristles in males accompanied by 15 – 20 hairs, which are only a little shorter than the frontal bristles. Females: sternite 7 (shiny black) shorter than sternite 6 ……………………………………………. cana (Meig.)

– Thorax before the suture with two widely spaced black middle stripes.  Basicosta clearly lighter than the tegula. Calyptrae yellow. Three katepisternal bristles. Frontal bristles in males only accompanied by 4 – 8 short hairs. Females: sternite 7 much longer than sternite 6 ……… grandis (Egg.)

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