Uric acid is the chief nitrogenous component of the excretory products of

Uricotelic animals excrete nitrogenous waste as uric acid, in the form of a pellet or paste, with minimum loss of water. Reptiles, birds, land snails and insects are uricotelic.
The cockroach is an insect; its Malpighian tubules remove nitrogenous wastes, which are excreted as uric acid.
The adult frog and man are ureotelic (urea is the main waste).
The earthworm is mainly ureotelic or ammonotelic, depending on the availability of water.
Hence uric acid is the chief nitrogenous waste of the cockroach.