INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 51 



legumes. Under marsh conditions the habits of oviposition have been 

 modified to a considerable extent, and the egg clusters are placed upon 

 rice stems and in clumps of grass from 1 to 2 inches above the water 

 level. In certain cases they were also found in the folds of cotton 

 leaves and in folded rice leaves. In India breeding is practically 

 continuous throughout the year, and the duration of the egg stage 

 ranges from 15 or 17 days in April to 41 days in the cold season. 



Another acridid abundant in Japan, Chosen, Taiwan, and China is 

 Locusta (Pachytylus) migratoria var. danicus, which is very injuri- 

 ous to rice, barley, millet, Panicuon sp., and various other cereal and 

 forage crops. It is of migratory habit. 



A pentatomid, Aenaria lewtisi (108), is at times very injurious to 

 rice in western Honshu (Ishikawa and Fukui Prefectures) and occurs 

 also in Taiwan and Okinawa. There is a single generation each year 

 and the winter is passed in the adult stage under stones, in rubbish, 

 and in other sheltered places. The eggs are laid in groups upon the 

 foliage and hatch in about 10 clays. The larvae are at first gregar- 

 ious, but later solitary, and the insects in this and in the adult stage 

 are nocturnal in habit. 



Aenaria scotti (108), which is an important pest in Kyushu, is 

 found less commonly northwards, not being recorded from northeast- 

 ern Honshu and Hokkaido. The species is single brooded, the adults 

 passing the winter in rubbish, grass, crevices in tree trunks, etc., and 

 emerging during the spring to feed on various grasses. In August the 

 nymphs and adults attack rice and wheat, feeding upon the sap of the 

 stem and developing head. Control measures recommended are the 

 destruction of rubbish piles and other places of hibernation in the 

 vicinity of cultivated fields, the collection of adults by knocking them 

 into trays containing oil, and spraying shortly after the hatching of 

 the eggs. This last, however, is hardly practicable from the economic 

 point of view. 



Another pentatomid is Scotinophara (Podops) Iwida (1^6, 96) 

 found upon rice throughout Japan, except Hokkaido, and in Taiwan, 

 China, the Malay Peninsula, and India. It is particularly injurious 

 in northern Honshu. There is one generation a year, and the winter 

 is passed in the adult stage. The egg stage covers one week and the 

 larval stage one month. The adults and nymphs gather at the base 

 of the plant and suck the sap, but later in the season feed at the 

 head, thus preventing the maturing of the grain. According to 

 Kikuchi, the adults of this species are said to secrete a fluid which 

 they discharge when disturbed and which causes blindness in human 

 beings. A third species attacking rice and Panicum sp. is Eurydema 

 rugoswm. 



Of the Cicadellidae attacking rice in Japan the most important 

 are Deltocephalus oryzae, D. dorsalis, Cicadula fasiifrons, G. sexno- 

 tata, and Nephotettix apicalis var. cincticeps. In Taiwan the major 

 species are the first three given above and in addition N. apicalis and 

 Erythroneura subrufa. In Chosen they are C. fasciifrons and N. 

 apicalis var. cincticeps. Schumacher (166) has given a full list of 

 the Homoptera of Taiwan, with their food plants, and many species 

 are listed as attacking rice, but only the more important ones are 

 here mentioned. Okamoto (151) records 23 species as attacking this 

 plant in Chosen, but only 3 are mentioned as of importance. 



