SJJ8S5 OBSERVATIONS ON BLIGHT. 



one-twentieth part of the sums gained and lost by dealers 

 during the two years in question. 



The hop-fly makes its first appearance generally about the 

 12th of May, sometimes two days earlier, but almost inva- 

 riably between the 10th and the 30th ; and it is worth noticing, 

 that it usually appeal's on the same day in the four districts of 

 Kent, Sussex, Farnham, and Worcester. It always makes its 

 first appearance in the winged state, a solitary fly being found 

 settled very quietly here and there under the young leaves. 

 If the weather is warm, with mild kind rains during the last 

 twenty days of May, these flies begin to produce young ones, 

 which are very small, and are called deposit, or Jcnits. These 

 grow very fast, and in a few days become green lice, which is 

 merely a larger form of the same animal. These lice very 

 soon begin to breed, and so keep on, knits and lice, knits and 

 lice onli/, to so great an extent as to destroy the plant, when 

 they appear to die with it. I have never found that the deposit 

 of the hop-fly leaves the plant at all, or ever becomes a fly 

 while there ; in this respect differing from the Aphis of the 

 rose, guilder-rose, bean, &c., of which I have spoken above. 

 Frequently, when the weather in May has been dry, and cold, 

 and windy, the fly has been known to leave the plant, and 

 entirely disappear, even after remaining several days; yet 

 whilst it tarried showing very evident signs of being uneasy, 

 continually crawling about on the upper as well as under side 

 of the leaves, and leaving no deposit whatever. The direction 

 of the wind has nothing whatever to do with their first appear- 

 ance, but in a warm westerly wind they will take flight most 

 readily, and be thus distributed. The lice, when half grown, 

 chanoe the skins ; and 1 have often found the skins of very 

 large ones stuck to the leaves, and yet showing no opening 

 where the insect could have got out. I believe these are the 

 prey of a little parasitic fly, whose history I don't know 

 enough of at present to attempt to give it you here; they 

 have, however, other enemies ; and as these seem to offer the 

 only hope of checking the increase of these destructive 

 wretches, I shall give you a little account of them. 



You will never find a plant of any kind infested with the 

 Aphis, vi\i\iO\xi also observing a number of ants and lady-birds 

 among them, and also a queer-looking insect, like a fat lizard, 

 which is in fact the caterpillar of the lady-bird. Tlie connexion 



