springtail - Hypogastrura nivicola

The anal spines are not visible at all... Let us hope they are not 'over-flashed'. Next time you might try a darker background. In this way the spines will be visible clearly.
Keep trying to shoot the anal sacs ;-) If your digital camera can make short video clips you may try to video a ready to jump specimen (with bent back) and then you can choose afterwards the frame with eversed anal sacs as standalone picture.

… Frans Janssens, 16 March, 2007 - 5:30am

anal spines?

My camera doesn't have video capabilities, so I'll have to keep at it next time. I photographed this from a number of angles, and there doesn't appear to be any anal spines that are clearly visible.

… tom murray, 16 March, 2007 - 7:06am

If anal spines are absent...

then it is not Hypogastrura but another genus... The alternative blue hypogastrurid genera without anal spines are: Microgastrura and some species of (Para)Xenylla.
Microgastrura is max. 0.55 mm, so that is ruled out. It could be Paraxenylla then. To be sure we need a good picture of the eye patch. We need to count the number of single eyes. Also we need to check the claws: there should be only one claw; the smaller inner claw should be absent.

… Frans Janssens, 17 March, 2007 - 4:18am

another shot added

I didn't have a good picture of the eyes, but here's one showing the claw on the foot. I added a couple of shots of a larger one with anal spines found in the same area.

… tom murray, 17 March, 2007 - 9:26am