210 



REVIEW. 



Miyake, T. "Studies on the Fruit-flies of Japan. T. Japanese Oranfje 

 Fly." Bull. Imp. Acjric. Sta. Japan, Vol. ii, 1919, pp. 85-105, 

 Plates II-X. 



This excellent and well illustrated monograph deals with the Japanese 

 fruit-fly, Dac}(s tsueonis sp. nov. The insect is described in detail, and 

 the author also gives a good description of the external structure and 

 an account of the alimentary and reproductive systems. The larva is 

 discussed very fully and a good deal of information is given of its internal 

 and external anatomy. In the bionomics of the fly some interesting 

 features are brought to light. Thus, the imagines are strongly attracted 

 to citronella oil, like those of several other species of the genus. Rasp- 

 berry syrup is apparently almost equally attractive, but kerosene has 

 little or no value in this respect. 



There appears to be but a single generation in the year, and the 

 species is limited to the island of Kiusiu in its distribution. Its destruc- 

 tiveness usually amounts to from 10 % to 20 % of the orange crop, 

 but when severe it reaches 50 % . The ovipositor pierces the skin of 

 the fruit and reaches the pulp, where the eggs are laid; thick-skinned 

 oranges are for this reason usually exempt from attack. When the larva 

 is fully grown, the infested fruit falls, and pupation takes place in the 

 soil. No certain parasites of this insect have so far been discovered. 

 The author recommends capturing the flies by means of a kind of 

 racquet smeared with bird-lime; infested fruits should be collected as 

 soon as possible, and can be utilised for the preparation of citric acid. 

 Storehouses should be improved and provided with hard floors, in order 

 to prevent any larvae issuing from infested fruit from entering the earth 

 for purposes of pupation. Tlic pa])(M' coiuludcs w ifh descriptions of five 

 new Japanese Trypaneidae. 



A. 1). T. 



