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the matting itself is attacked, so that a double covering affords no 

 protection. This moth dies in piles of fermenting leaf and attacks 

 the surface-layers only of baled tobacco, probably because of the 

 presence of the gases mentioned above in connection with L. serricorne. 

 The larvae usually pupate in the bale close to the covering. 



A temperature of 109° F. was found to kill all stages after 5 hours, 

 while a low temperature of 32° F. has the same effect after 120 hours. 

 Thus it may be assumed that S. margalaestriata cannot survive the 

 winter in Holland. 



The various methods of disinfecting tobacco are very fully reviewed. 

 Experiments were made to see if an economy in carbon bisulphide 

 could be effected by prolonging the fumigation. The following 

 minimum quantities are recommended, either to free tobacco bales 

 from L. serricorne or S. margalaestriata., or as a precautionary measure : 

 (1) 185 c.c. per 35 cubic feet for a period of 24 hours ; (2) 100 c.c. for 

 48 hours ; (3) 80 c.c. for 72 hours. It should be noted that in Besoeki 

 6-8 bales of tobacco average about 105 cubic feet. If the tobacco is 

 not baled or pressed, 32 c.c. per 35 cubic feet will effect disinfection in 

 36 hours. Other substances also were tested in these experiments, 

 which are described in detail. Acetylene appears to provide a substi- 

 tute for carbon bisulphide, proving fatal under experimental condi- 

 tions when 1 oz. of calcium carbide was used per cubic foot. Sul- 

 phuretted hydrogen also appears suitable, but the quantities required 

 were not worked out. Hydrocyanic .ncid gas was found unsuitable. 

 Bales that have been disinfected may become infested again from 

 adjacent infested ones, but if stored in clean warehouses, they may 

 be kept free from attack for years. Other infested produce, such as 

 ground-nuts, cacao, coca, etc., are sources of infestation and this also 

 applies to infested manufactured tobacco imported from Holland. 

 The author suggests that tobacco leaf intended for shipment from Java 

 should be covered by a fmnigation certificate issued by the Experi- 

 ment Stations. Fumigation must take place at least 7. days before 

 shipment in order to ensure that all fumes have dispersed. The 

 wharves must not stack other (non-disinfected) produce near the 

 disinfected tobacco, and the steamship companies must also observe 

 this rule when stowing the cargo. All manufactured tobacco must 

 be disinfected before it is exported from Dutch and other ports. 



Both in the bales and in the sweepings other insects are found 

 besides L. serricorne and S. margalaestriata. A small Ichneumonid 

 of the genus Norbanus parasitises the pupae of the former. A mite 

 of the genus Rhagidia also occurs, but the author has never observed 

 it destroying the eggs or larvae. A beetle, GonocephaJum hoffmann- 

 seggi, Stev., which closely resembles G. acutangulmn, is not uncommon 

 in packing sheds. Its larva attacks maize and rice and probably 

 tobacco. G. hoffmannseggi has been found only in tobacco infested 

 with S. margalaestriata., and remains of the moth have been found in 

 the stomach of the beetle, which however appears to be only a scavenger, 

 for neither it nor its larva have ever been seen to attack living moths 

 or caterpillars. A Carabid beetle is an active enemy of the larvae of 

 8. margalaestriata and of the larvae and pupae of L. serricorne, while 

 the larval and adult forms of a Clerid, Thaneroclenis hiqueti, Lef., 

 actively prey upon Lasioderma larvae. None of these natural enemies 

 are of real economic importance. 



