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Botanic Garden at Sydney, informs me that a tree now in that 

 garden was planted about six years since ; and I found it had in that 

 time attained the height of 35 feet ; but the top of the tree having 

 been cut off at an early period of its growth, it had divided into 

 several branches. This had retarded its growth as far as regards 

 elevation, although (as was the intention) it had promoted the ex- 

 tension of its branches : and, but for this circumstance, it might 

 have been expected that by this time the tree would have attained 

 the elevation of about 60 or 65 feet. The leaves of this species of 

 Eucalyptus, on being bruised, yield a delightful citron-like odour, 

 compared by some to the smell of balm, and by others to the scent 

 called Citronella ; and when the leaves are dried and placed among 

 clothes or papers, they impart an agreeable scent to them. Consi- 

 dering that it might prove useful in an economical point of view, I 

 procured a quantity of the leaves, which were distilled by Mr. 

 Norie, a practical chemist in Sydney ; and it was found that three 

 pounds twelve ounces weight of the leaves yielded by distillation six 

 drachms and a half of a pure colourless oil. A very small number 

 of drops of the oil (about eight), to an ounce of spirit, produce a 

 very powerful and agreeable perfume, approximating to that known 

 as Citronella, which may be called " Essence of Lemon-scented 

 Gum-tree." I sent some of this oil in its pure state to Sir William 

 Hooker, through my friend Dr. F. Muller of Melbourne, to be 

 placed in the Museum of Economic Botany. When the outer bark 

 of the tree was hanging in strips upon the trunk and branches, as 

 is usual with the Eucalypti, the new bark underneath was of a deli- 

 cate greenish white colour. A red gum exudes from this tree. As 

 this tree may eventually prove of great utility in affording perfume, 

 every exertion will be made to propagate it in the neighbourhood 

 of Sydney, and being of rapid growth it will, no doubt, quickly suc- 

 ceed. About September I observed a gregarious Caterpillar feeding 

 upon the foliage of this tree and rapidly destroying it. On a closer 

 inspection I found the larvae of a species of Perga or Saw-fly, 

 huddled together both on the upper and under sides of the leaves, 

 arranged for the most part in regular rows. When disturbed, they 

 simultaneously bent their bodies in the form of an arch, and emitted 

 a greenish fluid from their mouths, as if to intimidate the intruder, 

 forming, on a small scale, a representation of an angry cat when a 

 dog approaches her lair. When put into a box, the larvae emitted 

 so powerful an odour of the leaves on which they had been feeding, 

 as to scent the room in which they were placed. The larva of the 

 Perga is evidently an omnivorous feeder, as it has been observed 

 upon several species of the Eucalyptus as well as on the Callistemon. 

 On showing the larva to my friend A. W. Scott, Esq., of Ash Island, 

 he informed me that he had made drawings and magnified dissec- 

 tions of this and other species. In a few days I received the ac- 

 companying description of this species, together with the beautiful 

 and accurate drawing (copied in PI. LXII.) by his daughter, Miss 

 H. Scott. 



