The Excretion of Ammonia and Uric Acid during the Larval Life of Certain Muscoid Flies

Abstract

1. Uric acid is present in small amounts, as a true catabolite, in tissues and excreta of larvae of Calliphora erythrocephala Mg. and Wohlfahrtia vigil Wlk. 2. The excretion of ammonia increases commensurate with the rise in body weight of the larvae, lagging a day behind it in Wohlfahrtia, this lag being almost absent in Calliphora; it falls off rapidly a few days before, finally disappearing at pupation. 3. The excretion of uric acid is similar in its course, but in much smaller amount. 4. The adequacy of casein as the sole caloric source, and the low biological value of ovalbumin, is demonstrated in Calliphora. 5. The pure protein (casein) diet involves an excretion of ammonia and uric acid about twice as great as the normal meat diet.