INSTITUTE, PUS A, FOR 1917-18 



87 



the name, so that the larvae seem fairly safe from such whilst 

 they remain in the stubble. Towards the end of the season 

 many Schcenobius larvae were found dead and dry inside 

 the stubble, but dead larvae of the two species of Chilo were 

 rarelv met with. This fact is in accordance with the habits 

 of the larvae, those of Schcenobius being extremely sluggish 

 and too slow to move to safer quarters when climatic condi- 

 tions in the stubble become unfavourable. The following 

 table shows in detail the main facts about these hibernating 

 larvae : — 



During this last examination, in the third week of 

 March, it was found that the percentage of dead in the total 

 number of Schcenobius larvae found was about 66 in the case 

 of stubble which had been ploughed some time previously 

 and allowed to lie exposed to the sun, whilst it was only 28 

 in the case of larvae found in the unploughed stubble. The 

 simple process of ploughing the stubble at this time of year 

 had therefore brought about the death of a very large per- 

 centage of Schcenobius larvae. Before advocating this as a 

 routine practice, however, further observations are desir- 

 able. Further work on these rice-borers was discontinued 

 at the end of March when the adults began to emerge in the 

 Insectary from the larvae collected from the stubble. 



In recent years crabs have come into prominence as pests 

 of rice-plants in the Indian Empire, and, although not 

 strictly subjects for entomological investigation, some work 

 has been done on them in their capacity as crop-pests, 



