Excretory tubules opening into the midgut which function to remove nitrogenous wastes in the form of uric acid. Synapomorphy of the Myriapoda+Insecta. Convergent in Arachnids.

the main excretory organs of insects. They primarily function in elimination of nitrogenous wastes and the maintenance of internal ionic balance.

The excretory organs of insects; a set of long tubules that open into the gut. PICTURE

These tubes are like a cockroach kidney and they squirm or writhe like snakes. They are filters that keep the cockroach's blood clean. (Weird name, nice function.)

The organ of blood filtration in arthropods.