No. 1. ] Miscellaneous Notes, 23 



surface. Length '04 incli, and breadth "025 inch. When laid, they take the form of 

 flattened ovals, with the lower side following the shape of tlie object on which they are 

 laid, and the upper surface convex. 



"iarya.— General colour bluish-green, tinted above with pinkish bronze. The 

 four anterior segments being less tinted than the remainder ; the young are almost 

 wholly of a rather dull pink. Length of adult '86 inch, breadth "15 inch. 



" Pupa. — General colour warm brown, darkening towards the tail, wing sheatli8 

 dull green for the first few days, after which they become dark brown. A dark me- 

 dian line from tail to thorax on the dorsal aspect. Length '5 inch, breadth '17 inch. 



"The caterpillar of the pomelo mjth is able to pierce uninjured the natural 

 defences of the fruit. Disregarding both the pungent oil of the rind, and the thick 

 layer of pith beneath it, it reaches the cellular portion of the fruit, which it tunnels 

 through and through in all directions, passing through the seeds if they happen to be 

 in its line, but apparently not seeKing them out. Faecal matter is deposited in the 

 burrows, and decomposition as a consequence quickly sets in on its walls. Under the 

 microscope the fluid contents of any cell which has had its containing sac broken 

 by the passage of the caterpillar is seen to be teeming with bacterial life of many 

 kinds. Carefully detaching a sac adjoining one that had been broken by a caterpillar, 

 but which was in itself quite perfect, and microscopically examining its contained fluid, 

 there appeared many bacteria. The most frequent form being masses of cocci, many 

 other forms were present, but in smaller numbers. 



"An oval saccharomyces was very plentiful in the injured cells, and is the probable 

 cause of the acid fermentation which takes place in them. It was not present in the 

 adjoining unbioken ones. Presumably the smaller forms only can pass from cell to 

 cell through the connecting vessels. 



" It is probably to this secondary attack of micro-organisms that the premature 

 ripening and falling of the fruit may be ascribed, more than to the actual injury done 

 by the caterpillars themselves ; other insects taking advantage of the holes made bv 

 the caterpillars throueh the rind can enter the fruit and lay their eggs in the pith and 

 pulp, with the result that large rotten patches spread from the entrance and exit 

 holes. These insects are two or three species of flies, and a small brown beetle, all of 

 which are attracted by any decaying fruit. 



" The life-history of the pomelo moth shows that there is only one period of its 

 existence when there is any hope of destroying it in useful numbers, and that is when 

 it is in the caterpillar stage inside the fruit. The eggs are small, and so like the oil 

 cells on which they are laid that without a lens it is difficult to see them ; in the pupa 

 state, which is passed beneatli the ground, they are well out of reach, and in the per- 

 fect stage, being strictly nocturnal and very inconspicuous, there would be little chance 

 of doing any good. 



" The only suggestion that I can make is to destroy all fruit that is seen to be in- 

 habited by the caterpillars, or which falls from the trees. The destruction of the 

 fruit which falls is of importance, not only as a means of killing the insects contained 

 in it. but also as preventing its serving for the rearing of another brood. 



" As the eggs seem to be laid only on the fruit itself, it would appear that if the 

 young fruit is put into bags, that they would have a chance of arriving at maturity. 



" 1 am inclined to think that the wild species of Citrus, \vLOVin by the native name 

 of i«wJ«2c ^erSaw, and which is apparently nearly allied to the pomelo. Citrus de- 

 cumana, is the natural food of these caterpillars, as it is a fairly common tree in the 

 jungles of some parts of Perak. 



" Since writing the above, bagging the fruit in common tliin white cloth has be-n 

 tried, in the Government gardens, with complete success. 



•' Quite recently I have found that the common limes, and also Pluropean lemcuis 



