All onychophoran species for which the diet is known are
carnivores, attacking and eating isopods and spiders (A-20),
crickets and termites (A-21), and molluscs (A-26). When hunting
or disturbed, velvet worms squirt secretions from adhesive
glands (Figure B), modified nephridia that open through perforations
in oral papillae beside the mouth. This spray congeals
into bitter, elastic, sticky white threads, entangling and immobilizing
their prey. An onychophoran holds prey to its mouth
by sucking, then slices off bits with bladelike jaws, and liquifies
tissues inside the prey with saliva secreted from salivary
glands behind the jaws. While waiting for prey to be liquified,
the hunter consumes much of the proteinaceous threads and
then sucks in its liquid diet. Food passes through the mouth,
pharynx, and esophagus; the internal organs are suspended by
mesenteries within the body cavity. The midgut secretes a tubular
peritrophic membrane, which encloses the food, and deposits
uric acid on the inner side of the peritrophic membrane.