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Chrysophtharta bimaculata is a serious pest of eucalypt forests in Tasmania. The beetle overwinters as a diapausing adult, but it is poorly documented whether it forms overwintering aggregations or where it shelters. During winter 1992, we searched 386 possible overwintering sites for C. bimaculata in Eucalyptus obliqua forests. Fourteen types of habitat were identi®ed, of which clumps of Gahnia grandis sheltered the greatest mean number of insects (3.31 0.72 insects/plant, n 65 plants), while bracken fern litter sheltered the least (0.14 0.14 insects/sample, n 7, 1 m 2 quadrat samples). Of the 14 habitat types, all except two (under the bark of eucalypt stags and in G. grandis clumps) were more often unoccupied. Beetles were more commonly found on mature forest edges or in logged and regenerating forests; few were found within mature forests. Our results show that C. bimaculata rarely forms overwintering aggregations of greater than 20 individuals per site, nor does it appear to have a signi®cant pre-diapause dispersal.

Both manual and automated techniques have been developed for the determination of phosphorus in the presence of iron(II1). Interference from iron(II1) has been substantially eliminated by its reduction with hydroxylammonium chloride prior to the formation of the molybdophosphate blue complex using ascorbic acid. The small but reproducible error due to the formation of iron(I1) is dependent on the iron to phosphorus ratio present in the digest solution but is significant only when this ratio is more than 500.Both methods have been applied successfully to the determination of phosphorus in digests and extracts of soil materials where the ratio is far below the value of 500, thus making a correction unnecessary.

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