i'm guessing it is a thrip or thunderbug
my office is in rural lancashire and we get infested with them once a year
it's great fun trying to use a mapping program when one of the pecked lines starts to move!
( mns 2️⃣2️⃣9️⃣0️⃣7️⃣, Tue 28 Jun 2011, 23:25, archived)