464 SCIENCE PROGRESS. 



the month, the generative organs mature, and copulating 

 specimens may be captured. The eggs are laid in moist 

 earth and hatch in six to eight days. The larvae feed on 

 the cane roots for a couple of months or more, as many as 

 sixty having been found upon one plant. The pupal stage 

 lasts for a week, and the beetles, emerging, cause the March 

 flight. These, on dissection, are seen to have empty ali- 

 mentary canals, and extremely rudimentary generative 

 organs. After feeding for a certain time, the beetles now 

 cease to leave the ground at night, are less abundant as the 

 east monsoon (April) brings the drier weather, and later 

 disappear till the succeeding west monsoon, with its rains, 

 causes a sudden resurrection. These observations point to 

 a yearly brood of young in December. The means adopted 

 is, therefore, to catch the beetles when they appear after 

 the rains, and before they have laid their eggs.^ Enormous 

 numbers are obtained by shaking the leguminous plants near 

 cane-fields over sheets at night, and large quantities are also 

 obtained by loosening the earth under such plants during 

 the day."^ 



The collection of moth-borer grubs is carried on in the 

 young cane-fields. Plants attacked are readily noted at 

 that stage and destroyed with their contained grubs. Later 

 on, when the canes become large, it is difficult to penetrate 

 the fields, and, furthermore, it is difficult to obtain a cane 

 which is not attacked, so that the destruction of infected 

 canes when well grown would practically mean the reaping 

 of the whole crop.^ 



This destruction of moth-borer grubs and mature 

 Wawalan beetles before they lay their eggs may be 

 taken as typical of this class of carefully thought out 

 remedies. The indiscriminate liming, trashing, treatment 

 with insecticides and burning have less to be said for them. 

 Owing to the nature of the growth of the sugar-cane, its 

 parasites are peculiarly inaccessible to ordinary methods of 

 treatment. The burning of fields is frequently the only 

 means of reaching them, and this is a step with very grave 

 consequences in the Tropics, because of the destruction 

 ^ Zehntner. - Barber (i), p. 301. ^ Watts. 



