• Poisonous, predaceous and fluid - feeding terrestrial carnivores.

• Male and female exhibit sexual dimorphism.

• Body has two divisions – Prosoma and Opisthosoma.

• Prosoma is covered dorsally by a carapace.

• Chelicerae provided with poison glands and serves as poison fangs.

• Opisthosoma is soft, ovoid and apodous, except for spinnerets and book lungs.

• Spinnerets make silk threads from viscous secretion of silk glands.

• Nocturnal.

• They have powers to regenerate their lost leg.