Flower thrips were reared on pollens and honey solution through thin membranes in glass vessels. Both sides of the glass vessels were covered with stretched Sealonfilm(R) membranes on which the thrips and pollens (of tea, pear, strawberry, tulip and pine) were placed. A drop of 10% honey solution was placed on the membrane and covered with another membrane to allow the insects to feed on the solution and lay eggs in it. Without pollen, young larvae of Frankliniella intonsa were unable to grow and adult females laid only a few eggs. The larval and pupal growth by artificial rearing was better than that on strawberry leaves and tomato fruits. The rate of emergence was higher than 85%. Thrips hawaiiensis could be also reared by the same method. Owing to the presence of pollens, flower thrips could lay large numbers of eggs and complete their whole life cycle. Mass rearing of flower thrips is practically possible by this method. Fig. 1. Rearing apparatus for flower thrips.

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A certain number of small brown planthoppers, having red-colored eyes, was obtained in F2 by crossing within general black-eyed small brown planthoppers collected from the field of our experiment station at Sapporo in October 1962. The occurrence of redcolored eye of this species seems to be new record. Inheritance of red color in eye was studied and was found to follow the Mendelian simple recessive gene explanation. Some ecological characters of both strains, black and red eyed, were compared but notable differences were not pointed out in preoviposition period, percentage of hatching, mortality at nymphal stages, nymphal growth, percentage of the appearance of the macropterous females, relation between renewing interval of food and the percentage of appearance of the macropterous females, phenomenon of diapause, acquisition and ability of transmission of the northern cereal mosaic virus. But certain differenses were recognized in sexual proportion of emerged adults, oviposition period, and number of eggs laid. The redeye individuals were not found in the field, and the red-eye strain does not differ from the black-eye strain in its behavior. Accordingly, it may be possible to utilize the red-eye strain as a marked indvidual in the study of relation between transmission of viruses and ecology of this species.

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