1(32 Bullelin de ht Société Eìiiomolo(]i<iiic d'iùjijplc 



II. A Note on the Rice Field Fly 



Ephydra macellarla Egger. 



This lly is frcciucntly accused by ramiers of causing 

 the death of cousiderable areas of rice in the northern 

 part of Lower Kgyj)!. To me this insect has been always 

 something of a mystery since so far I have been un- 

 able to convict any one of its stages of Ihe injury lo rice 

 with which it is credited by the rice-grower. At present 

 I am of the opinion that this lly is more in the nature of 

 an effect than the cause of the death of young rice. 

 This Ephydra will frecjuently be found in that part of a 

 rice field or rice growing area which is most sally, or 

 again where voung rice plants have been washed out by 

 wind action on the water and carried to the sides of the 

 little basins or hods, and there commenced lo decay. 

 These two factors — the presence of salt and decaying 

 vegetation — are favourable to members of Ihe family 

 Ephydridae including H. macelhirid. 



The life-hislo!v of this epecies is brielly as follows. 

 The female Hies dro]) their small slighlly curved eggs, 

 which are at lirsl whitish and later i)inkish in colour, 

 on the surface of the waler, whence they sink to the 

 bottom. The eggs are also laid in great numbers on the 

 scum or froth which may be formed on Ihe surface of 

 the waler: also on lloating debris, the surface of which 

 is thoionghly wet. The eggs hatch into small active 

 larvae characleiized by a forked [)rocess — part of the 

 breathing organs — at the jioslerior exlremity ol the bo- 

 dy, and the |iresence of numerous shaip t'ur\c'd hooks 

 placed on the pseudopodia on the ventral surface of the 

 body. By means of these hooks the lar\a can cling to 



