From Citizendium, the Citizens' Compendium
Jumping bristletails (Order Archaeognatha) were once classified with true bristletails, as they have a characteristic 3 long filament-like tails.
Jumping bristletails are wingless, medium-sized insect measuring around 15mm in length, excluding the tails and antennae. They are generally a brownish color. They have compound eyes which are so large they occupy most of the head. They also have styli, movable fingerlike projections, on their abdomen.
Jumping bristletails live under rubble, loosely piles stones, leaf litter or bark in grassy or wooded areas, and in rocky cliffs next to the sea.
Jumping bristletails were once considered part of the now defunct order Thysanura. Later, they were given their own order, Microcoryphia, which has since been supplanted by the current name, Archeaognatha.
Number of species
There are 25 species found in North America, and 350 worldwide.
There are two families in this order, distinguished by differences in scales at the base of the antennae, and the number of pouches, or vesicles, beneath each abdominal segment.