Abstract
The author has performed experimental, morphological and physiological studies on the colouring phenomenon of the body surface of the newly moulted larvae of some strains (brown spotted larva, E 18 and N115 etc.) which coloured on the surface of epicuticles. The results obtained are as follows:
When the secretory substance from the dermal glands of alveolar type is mixed with that from the granular one the coloration on the body surface appears in the newly moulted larvae. This was ascertained at the surface of the new cuticle underlying the old one by means of ligature experiments at a boader of two types, i. e., between the 6th and 7th segments. This fact suggests that chromogen is secreted from one of two types of the glands while enzyme oxidizing the chromogen is from the other.
Especially in both the species, the brown spotted larva and E18, some chracteristic brown spots appear at the openings of the alveolar-type-glands. This fact appears that the forming mechanism of the spots is the same as above-mentioned colouring phenomenon.
Since phenols such as tyrosine, catechol and p-cresol, are oxidized by the secretory substance from the alveolar-type-glands, a phenol oxidase seems to be contained in the secretory substance. Although there is a metabolic path way from phenylalanine to tyrosine as shown by Haldane (1942) in man and by T. Fukuda (1955, unpublished) in Bombyx, the phenomenon which phenylalanine is coloured by the secretory substance is unable to be explaned with the author's experiment. On the contrary, the above-mentioned phenols are not oxidizable by the secretory substance from the granular-type-glands. By this fact, it seems that in the granular-type-glands the enzyme exists in very few, even if it is present, or does not. Phenylalanine is not coloured by the secretory substance.
