On the Life-History of Ugimya Sericaria, Rondani. 



By 



C. Sasaki, Riéakusbi. 

 Professor in the Agricultnral find Dendrological College, Tokyo. 



With Plates I— VI. 



In Japan, the silkworm is reared at four different times of year, 

 viz ; — in May, July, August and September. It is however reared 

 on a large scale only in the month of May, comparatively much fewer 

 in number being raised at other times. 



The so called " Uji " disease caused by the larva of a diptera 

 Ugimya sericaria, Rond, plays terrible havoc among the silkworms 

 reared in May and July. When the silkworm is once infested by this 

 parasite it dies either before or after it spins a cocoon ; in the latter case 

 the maggot eats its way out of the cocoon thus leaving a round hole in 

 it with the consequence of making it unfit for reeling. In the spring 

 or May breed of silkworms some 50 to 70 °/o or in extreme cases 

 80 "/o are attacked by tlie parasite, and the damage done is corres- 

 pondingly great. 



Fatal as the " Uji " disease is to the silkworm, no systematic 

 observations have hitherto been made on the habits and life history of 

 the maggot. The fragmentary observations recorded are very im- 

 perfect or erroneous. The first who gave a brief account of this parasite 



