1. 30 g. of the excreta of Melanoplus bivittatus on a restricted diet of lettuce were obtained from all stages of the insect.
2. Over 20 per cent of the excreta consists of the peritrophic membrane; the negligible nitrogen content of this element indicates that it cannot be chitinous.
3. Enclosed within the membrane are the food residues, and encrusted on the outer surface are the urinary constituents.
4. Uric acid is the predominant nitrogenous catabolite; methods of its extraction from excreta are compared.
5. The presence of urea is demonstrated by two methods, as also is a significant amount of amino nitrogen.
6. Creatine is absent, but arginine is present.
7. The presence of phyllobombycin in the ether extract was indicated by spectroscopic properties.