Earlier this month I blogged about the mysterious ‘things’ I had discovered on the needles of some local Pine trees (Mystery: on a Pine tree, 10 April). Well, the mystery has now been partly, but not entirely solved.
Last Friday, the 18th, I was making a sandwich for lunch when I noticed a change in one of the ‘things’. A creature had obviously made itself a hole in one end and was very slowly squeezing its way out. I quickly grabbed a camera, though it was neither easy to get photos looking in to the little jar, nor through the glass sides.

The tiny creature crawled unsteadily across the bottom of the jar then climbed one side, where it clung as its wings slowly dried and unfurled. Its bright pink colour was a lovely surprise.

So, the ‘thing’ was a pupal case or cocoon but I’m still not completely sure what the creature was. Some online research led me to think it was some kind of midge or gnat, and that was later confirmed by the Dipterists forum folk on social media: ‘one of the midges in family Cecidomyiidae’. I researched further, trying to find a similar-looking external cocoon or an association with Pine trees within that family of midges but found nothing in the UK that seemed to fit. I did find some US references to Cecidomyia piniinopis, which looks very similar, but that species is not listed in the taxonomy for Britain.

Still, I’m pleased I managed to at least partially solve the mystery and seeing the adult midge emerge was quite special. It, and the other cocoon, have been returned to where I found them to, hopefully, live their best lives.