The fangs of a tarantula lie in a groove in the chelicerae, each of which contains an elongated venom gland. Venom leaves the glands through a channel at the tip of each fang.
Tarantulas typically pounce on their prey, simultaneously piercing the prey and using chewing movements of the chelicerae.
The spiders must liquefy their food outside their body. Chewing movements of the chelicerae liquefy the prey, which is squashed to a wet pulp. Contents of the ball of prey are slowly ingested.
After feeding, the remaining indigestible remains are deposited far away from the main living location of the spider. In the case of the two Mexican red knees, the remains are left next to their water bowls.