Malpighian tubules are
Malpighian tubules are excretory organs of insects. These are unbranched tubules lying almost freely in haemocoel and open into alimentary canal. The main function of these tubules is to absorb nitrogenous waste product.
Spiracles are the respiratory systems of insects through a series of external openings.
In primitive annelids, each compartment of the coelom is connected to the outside by ducts for the release of sex cells, and by paired excretory organs, or nephridia. Some aquatic annelids have thin-walled, feathery gills through which gases are exchanged between the blood and the environment. However, most annelids have no special organs for gas exchange, and respiration occurs directly through the body wall.