The riboflavin of feedstuffs used in Japan for poultry. is determined (Table 1). Among them the silkworm pupa has a very high riboflavin content as the author alrealy reported*, and the feeding experiment shows that the defatted pupa is a good feedstuff both as riboflavin supplement and protein source (Tables 2 and 3). The pupa solubles have the highest riboflavin content.* T. KOYANAGE: Bull. Imp. Seri. Exp. Sata. 9, 205. (1939).
