I finally ran accross some more of these convex, discoid mites that look superficially like beet*les. The last time I found them I was far more interested in shooting the tiny hister*id beet*le that was climbing on them and didn't even think to shoot their topsides.

These were in a small, fungus-lined pocket or cavity in the sapwood of a deciduous tree that appeared to have been drowned several years back by a beavers' dam. The bark was loose, missing, or encrusted with tree fungi. It was still in shallow water from snow melt and I waded out to it in my rubber boots, hacking into the sapwood with my sharp hatchet to see what might be living in there.

Besides these mites I found a number of teneb*rionid larv*ae, a horn*tail larv*a and a weird-looking Pityo*bius clic*k beet*le larv*a all living in this tree. (Asterisk use is to avoid this image being shown in searches on those words.)