1. In vivo studies on 5th instar and adult locusts revealed that chitin formation in thorax, abdomen, hind leg and wing was greatest during the first few days after moulting.
2. Wing extracts were used for in vitro experiments, and evidence was obtained for the presence of the following enzymes: hexokinase, phosphohexose isomerase, glutamine transaminase, phosphoglucosamine transacetylase, acetyl coenzyme-A synthetase, phosphoacetylglucosamine mutase and uridine diphosphate N-acetylglucosamine pyrophosphorylase.
3. The results are discussed, and a tentative scheme is presented for the biosynthesis of chitin in the wing of Schistocerca gregaria.