478 Mr. W. S. MacLeay on Ceratitis Citriperda, 



oranges is much greater from St. Michael's than from Lisbon, differences 

 that can scarcely be supposed to result from their voyage to England. 

 Now the decay of the St. Michael oranges, which form the great bulk of 

 those brought to the London market, is towards the end of their season, 

 namely, during the months of March, April, and May, almost universally 

 accompanied by the presence of the larva of a small fly, which I shall 

 shew by observations made by a friend in the Isle of France, and by my- 

 self in London, to be the cause of the evil. Whether the Lisbon oranges 

 suffer from any similar insect, I have not been able accurately to ascer- 

 tain, but sure it is that the general symptoms of decay are much the same 

 in both cases, so that there is at least great reason to suspect it. As for 

 the St. Michael oranges, towards the end of the season whole chests are 

 destroyed by this fly, specimens of which are easy to be procured, as they 

 may be bred from the larvae which are to be found in almost every one 

 of those damaged oranges which our barrow- women display for sale in 

 the month of May. Those worthy collectors, however, that confine 

 their attention to British insects, need not place it in their cabinets, as I 

 find they have of late been doing with American forms. At least they 

 must first shew the orange-tree itself to be indigenous. 



On a first view of the subject, it would appear, that if oranges are 

 shipped in a damaged state, it must be certainly known to the shipper ; 

 but there is no good reason to believe that any such advantage is taken of 

 the London merchant, since oranges as frequently arrive in a damaged 

 state, when on account of the shipper, as when to the order of a mer- 

 chant. The truth is, that both parties being able to shift the burden 

 from off their own shoulders, it is a matter of comparatively little con- 

 cern to them what may be the cause of a general evil, and this cause 

 being moreover, in its nature, of that sort which requires a minute 

 investigation, it is not to be wondered at that it should have so long 

 remained unknown. I ought, however, here to state, that Mr. Trevelyan 

 having given my father some specimens of the insect, I was induced by 

 the singularity of its form to consult Mr. Mart of Oxford Street, the 

 respectable orange merchant who had called Mr. Trevelyan's attention 

 to the subject. It would therefore be a great injustice to Mr. Mart, if I 

 did not give him the full credit of having discovered the fly which is the 



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