752 



raOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 



Experiment XVII. 



The experiments in storing grain against insects were carried on at 

 Pusa where Trogodenna khapra does not occur. In order to find out the 

 eSect of sand on this insect this experiment was made when materials 

 were available. 



17th June . 



19th June ; 10 a.m. 



20th June ; 



21st June; 8i 



22nd June ; 8 a.m. 

 By 26th June 



100 beetles and 100 grubs about half to three-fourths 



grown were placed in a glass jar with sound wheat. 

 Fine sand was placed on the top of the wheat. Much of 

 the sand percolated down and a sufficient quantity 

 was added to keep the grains covered. 

 18 grubs and 16 beetles were observed to have come up 

 to the top of the sand, where they were crawling 

 about, apparently not being able to make their way 

 down through the sand. Eleven of the beetles were 

 dead. The insects are left on the top of the sand. 

 29 grubs and 18 beetles are found on the top of the 



sand. All are left there. 

 31 grubs and 19 beetles on the top of the sand. 

 58 grubs came up to the top of the sand. No more of 

 the beetles came up, as they were dead. 

 It will be evident from this experiment that sand will prove as effective a check 

 upon this pest as upon the other pests with which the experiments carried on at Pusa 

 were concerned. 



Experiments with rice (husked). 

 Experiment XVIII. 

 A parallel series of preliminary experiments was made with usna 

 rice (rice prepared after boiUng the unhusked paddy grains which are 

 then dried and husked) in small earthen pots with loose covers (Plate 

 111, fig. 3) and small gunny bags in the same manner and at the same 

 place as wheat in Experiments I to III. Two pounds of rice was used 

 in each recej^tacle. They were stored between 15th June and 1st July 

 1915 and the final examination was made on 20th March 1916, the 

 weights left on which date, after sieving out the dust, are shown in 

 the table below. The damage was done by Calandra orijzcB and there 

 were Tenehroides mauritanicus, Tribolium castaneiun and Lwmophloeus 

 pusiUus in almost all. 



