I was looking through the flies caught on the sticky trap in my greenhouse. I came across this fella (rather dead and crushed, sorry). I just need to know if it is beneficial or not. Could it be a form of thrips? It is about 9mm long.
FYI: thrips of 9 mm in your greenhouse would be worth calling the newspaper for. It would have been a veritable giant! Your big specimen is a hoverfly, a female of the genus Sphaerophoria, which often cannot be identfied to species level. Larvae of Sphaerophoria are aphid feeders, so you may consider it to be beneficial.
Thank you so much for your help. Sorry if it was a stupid question, but I am trying to learn from books and the internet, and I saw somewhere that thrips can be up to 14mm, so I was misled. It's pretty obviously a hover fly as you say. Very grateful - Isobel