Mine on Scots Pine, Highgate Common, Staffordshire, 21st February 2019.
Note there is no frass in the mine as it is ejected through one or two holes (hole visible at base of mine).
On Scots Pine, Highgate Common, Staffordshire. February 2019.
After initially mining a needle, feeding internally, the larva vacates the mine, spinning up next to a bud, boring into it to feed.