Abstract
The water-soluble proteins were isolated from the cuticles of 7 spp. of insects representing 3 orders. The protein prepns. were shown to be heterogeneous. By paper-partition chromatography the amino-acids present in acid hydrolysates of the proteins were identified. The amino-acids with free alpha-amino groups were recognized in 4 of the prepns. and the amino-acids with free carboxyl groups in one. All the water-soluble proteins, are remarkably similar in their physical and chemical properties, including component amino-acids and free amino groups.