Thanks for that link - I had a look at it and I'm pretty sure they are psocids (plus the odd plaster beetle, typeD: sylvanus bidentatus). But I'm still puzzled, though not overly worried, why they are there whenthe bales haven't been plastered yet, have been stored dry and well-aired.
Ah yes. I got so carried away with the prospect of more sexy psocid images that I forgot to say what I wanted to say. Sorry eh ?
Some speculation as to why you still have psocids even though the bales *appear* to be dry.
This year, here in Kanata (Ontario, Canada) it rained almost every other day during the month of June and those days where it wasn't raining have been very humid. It rained yesterday and will likely rain again today and the (hot)air is so humid right now my dog is dragging her tongue on the ground.
Under such conditions, I would expect that any material with hygroscopic tendencies (wood, paper, cotton fibre, concrete, soil etc) would have moisture contents that are at or near a maximum.
So if in fact the bales were dry, the larvae from dry straw could conceivably have migrated to any other material that might provide a more moist environment for them to propagate themselves but I suspect that the straw itself would be pretty moist simply due to the elevated levels of ambient humidity that we've been experiencing.
ie Actual moisture content @ 75% relative humidty in summer is substantially more mositure than even 90% RH in winter.
-- === * === Rob Tom Kanata, Ontario, Canada < A r c h i L o g i c at chaffY a h o o dot c a > manually winnow the chaff from my edress in your reply