The left colleterial glands of Blatta and Periplaneta secrete 4-O-β-D-glucosidoprotocate-chuic acid (I). B. orientalis and P. americana were cultured at 25° and the colleterial glands of mature adults killed by decapitation were dissected under saline soln. The fluid of oSthecae (12-8 ml., pH 5.6, pos. chromaffin reaction with 5% KIO3 and AgNO3 reaction for o-dihy-droxyphenols, NaOEt and observation of changes in min. and max. absorption in agreement with known values of substituted hydroxybenzoic acid Accordingly, II is stored as I by the left colleterial gland which also secretes the protein constituents of sclerotin and a polyphenol oxidase. The right gland secretes a β-glucosidase such that, in the intermingled secretions in the genital vestibulum, II is liberated and oxidized by the polyphenol oxidase to an o-quinone which in turn condenses with the protein to form the resilient sclerotin constituent of the ootheca.