The appendages of the 2nd somite of the opisthosoma absent, rarely minute and budlike (some Amblypygi), never pectiniform.
63,stg), as in the Amblypygi, or with the posterior pair, rarely the anterior pair as well, replaced by tracheal tubes.
Namely the Amblypygi of which Phrynus is a commonly cited type, these tactile appendages are exceedingly long and lashlike, whereas in the tailed division, the Uropygi, of which Thelyphonus is best known, the limb is much shorter and less modified.
Some species of the Uropygi (Thelyphonidae) dig burrows; and in the east there is a family of Amblypygi, the Charontidae, of which many of the species live in the recesses of deep caves.
The distribution of the Amblypygi practically covers that of the Uropygi, but in addition they extend from India through Arabia into tropical and southern Africa.