INSECTS INJURIOUS TO AGRICULTURE IN JAPAN 73 



are only two generations the adults of the first appear in late April 

 and early May, and those of the second the middle of July ; whereas 

 in localities producing three generations the adults of the second 

 emerge slightly earlier than the date given above, and those of the 

 third come in late August and early September. The larvae of the 

 third generation particularly are heavily parasitized by Apamteles 

 rapae Ash., and Uchida records two native ichneumonids attacking 

 it. The variety crwcivora is found in Japan, Chosen, China, etc., 

 feeding on various Cruciferae. Its habits are very similar to those 

 of the original species, though it is much less abundant. 



Considerable damage may at times be caused to cabbage, radish, 

 rape, and various other cruciferous plants throughout Japan and 

 Chosen by Evertfestis extimalis (149). The data on this species were 

 given under the name of Perynea swbrasea Butl., but Kuwayama ad- 

 vises that the determination was incorrect and that the name should 

 be given as above. There are two broods each year, the moths of 

 the first appearing in early June and those of the second late in July. 

 The winter is passed by the mature larva in a whitish cocoon in the 

 soil. Eggs are deposited by the females, shortly after emergence, 

 on the undersides of the leaves. The immature stages of this genera- 

 tion cover a period of six or seven weeks. The young larvae make 

 a web of special type, within which a number of them may congre- 

 gate. In the case of rape and such other Cruciferae as are grown 

 for seed the damage results from feeding upon blossom clusters. The 

 second-generation larvae feed also upon such Cruciferae as are avail- 

 able in the field. These larvae are mature and enter the soil for 

 hibernation at the end of September. 



Arctia cctia (165) is at times injurious to cabbage and rape in 

 northeastern Honshu and Hokkaido. A single brood is produced 

 each year, and the insects hibernate as immature larvae in rubbish on 

 the ground. These larvae emerge and feed upon foliage in the 

 spring, and pupate the middle of June among the leaves on the sur- 

 face of the ground. The adults appear the following month. 



The pyralicl Pionea forficalis (96, 11$) is at times a serious pest of 

 radish, turnip, and carrot in Japan. There are two broods annually. 

 The insect hibernates in the mature larval stage in the soil. In north- 

 ern Japan the adults appear in June and August, whereas in central 

 Honshu they are found in May and September. The eggs are de- 

 posited on the undersides of the leaves or on the stem, and the larvae 

 roll the leaves and feed upon the tissue of the underside. Pupation 

 occurs in the soil. 



The diamond-back moth, Plutella maculipennis (11$), is an occa- 

 sional serious pest of cabbage, radish, turnip, and other garden crops 

 in Japan, Chosen, and Taiwan, but little is known regarding its life 

 history. 



The chrysomelid Phaedon brassicae (95) is a pest of radish and 

 turnip in Honshu and Kyushu. There are three or four generations 

 each year, and the winter is passed in the adult form in sheltered 

 places. 



Phaedon ineertus is one of the serious pests of cruciferous vege- 

 tables in northern Japan, both larvae and adults contributing to the 

 damage. It occurs also in Taiwan. Nozu and Sonoyama (138) have 



