58 



.lOUKNAL OF TPIE ROYAL I KVHTlCULTllHArj SOCIpyrV. 



Pei-sonally I should fnvonr the npplicn(;ion of cotton-wool barriers, 

 wliicli, it' properly applii^l, would (ylToctually prevent the slugs from 

 reaching ilio l(\ify crcnviis of ilie plant. Tlie band should be applied 

 and secui'ed with siring at a height of one foot or more from the ground, 

 and should be at least two inches thick below the tie. The plants in 

 question must be kept free from weeds, so as to prevent the access of 

 the slugs by any other path than the stems of the rubber plants. 



Cabbage Butteefly (Pirris sp.). 



One of the commonest butterflies met with during my stay in tlie 

 island was a large white species which is very closely allied to the 

 " cabbage butterfly " (Pierls hrassicae) of this country. It seemed very 

 generally distributed over the whole island, but was nowhere so abun- 

 dant as in the swamps near Port Henderson, where it was seen flitting 

 about over certain favourite plants {Portulaca sp., &c.), frequently 

 congregating together in scores or hundreds, presenting to the stranger 

 a very remarkable sight. Its natural food-plant was not observed, 

 but larvse were found infesting cultivated crops, chiefly cabbage, to 

 which it seemed partial, and to which also it was very destructive in 

 the parish of St. Andrew. Examples of this butterfly were bred in 

 the laboratory from caterpillars which were taken from cabbage under 

 cultivation in the garden of Constant Spring Plotel. This was during 

 the month of December. In January there was a marked diminution 

 of both caterpillars and the butterfly. The larva feeds up very quickly, 

 though the exact period was not ascertained, and the pupal stage lasts 

 but a week or ten days, possibly less under more favourable conditions 

 than those under which they were kept in the laboratory. 



The infested plants had been dusted over at regular intervals with 

 an insecticide prepared by an American firm. That it was effectual 

 there can be no doubt ; but on discovering that it consisted almost 

 entirely of powdered hellebore the writer advised the cultivator to dis- 

 continue its use, fearing that it might lead to serious results, as large 

 quantities of the vegetable were being served at the table almost daily, 

 often, as the writer observed, with evident traces of the insecticide still 

 in the axils of the leaves. 



A Pyralid Moth Injuring Beetroot. 



Beetroots seemed particularly subject to the attacks of the cater- 

 pillar of a moth belonging, so far as one could gather, to one of the 

 small Pyralid group. In two localities the crops had been rendered 

 leafless by this pest. Unfortunately, time did not permit one to rear 

 the perfect insect, but this could be easily accomplished, and with little 

 trouble the whole life-cycle could be worked out. 



In this case a poisonous insecticide might be used with comparative 

 safety; and possibly Paris Green, at the rate of one ounce to twenty 

 gallons of water, will be found effective. 



