282 



spread. Whether it had been imported from Japan or is an endemic 

 species in Korea has not yet been determined. It has two broods in a 

 year, the adult of the first brood appears in May and that of the second 

 in the middle of July. It passes the A\'inter as a larva and pupates 

 in May of the next year. The eggs are laid on the epidermis of new 

 and soft shoots that are in contact with the ground, the newly hatched 

 maggots showing a marked preference for damp spots. If the tree 

 has split bark, the fly lays eggs in it, even if the fissure is some distance 

 from the ground. Larvae that appear on the epidermis bore under 

 the bark and eventually into the cambium. The bark often splits 

 as a result of infestation, so that the flies of the second brood usually 

 oviposit in the cracks produced, which thus often contain larvae in 

 two different stages. Infestation by the maggot causes the shoots 

 or branches to decay, so that they sooner or later die or break oft. 



As the midge mainly infests the young shoots that are in contact 

 with the ground, the best remedial measure is a system of pruning 

 that leaves only those shoots that are at least five inches above the 

 surface. An excessive amount of moisture in mulberry plantations 

 must also be avoided. 



Vedalia Tento-mushi oyobi Icenja Kaigaramushi ni Kansuru Kenkyu. 



[Researches on the Coccinellid Vedalia and the .Scale-insect 

 Icerya.] — Bijohin-gaichu Iho [Bulletin of Plant Pathology and 

 Injurious Insects], Dept. of Agric. and Commerce, Tokyo, no. 3, 

 25th November 1917, pp. 107, 11 plates, 3 maps. 



Icerya pnrchasi, Mask., having been imported into the Prefecture 

 of Shizuoka the principal orange-growing district in 1911, and serious 

 damage having been caused by it, the Imperial Department of Agri- 

 culture and Commerce entrusted the study of this pest, as well as of 

 its natural enemies, especially Novius cardinalis, Muls., to the Prefec- 

 tural Agricultural Experiment Station, and gave financial assistance 

 for the purpose. This report is the result of the investigations. 

 Novius cardinalis, when reared in breeding cages, appears to have 

 eight generations a year and winters in the larval stage. Out of 

 doors the life-cycle seems irregular, and eggs, larvae, pupae and adults 

 are seen at every season. It usually lays from one to three eggs on 

 the o\nsac, or within the body of Icerya purchasi, but occasionally 

 also oviposits under the cast skin of the host or on the leaves or branches 

 near by. The female oviposits over a period varying from six to 

 forty-four days according to the season, laying as many as 54 eggs in a 

 day in the summer ; in the spring and autumn sometimes only a single 

 egg is laid per diem. The number of eggs laid by a single female 

 varied from 54 to 816. Oviposition takes place to a greater extent 

 by day than by night. The first stage of the Coccinellid larva devours 

 only one or two larvae of I. purchasi in a day, while the last may destroy 

 as many as 46. In one case a Novius larva consumed 126 young 

 larvae of Icerya. The voracity of the adult differs in the sexes ; the 

 average consumption of the female was 213 scales of various stages 

 during 15 days, while the male destroyed 136 in 16 days. In the 

 spring the life of the female is 40 days and that of the male 22 days 

 on an average ; in the summer the female lives 23 days and the male 

 13 days. These Coccinellids prey on one another when food becomes 



