The 19 species whose colleterial glands were studied represent three types of egg-laying behavior—those that abandon the oötheca shortly after its formation, those that carry it externally during embryogenesis, and those that carry it internally. The glands vary in size from species to species according to the size of the oötheca elaborated. In Diploptera punctata they are not required during the development of the embryos in the uterus of the female, β-glucosidase is present in the right colleterial gland of cockroaches representing all three types of egg-laying behavior, and also in that of a praying mantis. An unidentified glucoside (Gl-A) was demonstrated by paper chromatography in extracts of the left colleterial glands of 19 species. This Gl-A occurs along with a glucoside of protocatechuic acid in seven species of the subfamily Blattinae; with a second unidentified glucoside (Gl-B) in two species, representing two genera, of Pseudomopinae. In nine other species, representing those that carry oöthecae either externally or internally during embryogenesis, Gl-A is apparently the only precursor of the tanning agent. The β-glucoside of protocatechuic acid was found also in extracts of left colleterial glands of praying mantids and in extracts of accessory glands of the twolined grasshopper.