By the way: DNA studies of these animals has lead to a new theory: they are actually not primitive insects, but primitive lobsters. That would explain the continuous shedding, even once adult, and the forked tail, not found in any other insects. For the time being we will leave them here with the insects, where they have been dealt with for centuries now. That might change within the next few years, though.
The species below is one of the easiest to identify. Still I needed George Tordoff to make the identification, for there are no good books, nor good sites about these little creatures, alas. Below one of the easiest species to identify: Orchesella cincta. In close up it even proofs to be quite well looking. It is a very common species all over Europe and is probably present in every garden, without ever being noticed. In the top pictures an adult, in the bottom pictures a juvenile.
Within the order of Springtails Orchesella is a remarkable genus, for their antenna exist of six members (parts). Usually Springtails have antennae existing of 4 parts only, but strangely Orchesella has 6. Now in its jumpy life something may happen to a Springtail causing part of the antennae to get lost. Not a big problem, for after the next peeling the antenna is likely to be restored. But this doesn't always happen in the right way. The animal in the bottom pictures apparently lost the first (or last) two parts of its right antenna. After the last peeling they were replaced by just one, very long segment. Just compare the left antenna to the right one. In Orchesella species this happens very frequently. In the 19th century scientists even thought this was characterisic of this genus.