194 PHILOSOPHICAL TRANSACTIONS. [aNNO l/OS. 



which their thin long wings were contracted and covered, between the bark and 

 the tree; and viewing it more carefully, I observed that these flies had made 

 their way thither by piercing the bark in innumerable places, easily discernible 

 on the outside, being about the size of a large pin-hole, or rather such as a 

 large pin's head would enter. Some of the flies I found just entering, having 

 got quite through the bark; others had made some progress between the tree 

 and the bark, which appeared as a channel. I despaired of recovering the tree; 

 however my servants being watering others, I caused them to bestow about 2 

 hogsheads on this tree, then stirring the earth about the roots, and laying some 

 half rotten litter about it, to defend it from the scorching rays of the sun; 

 npon this the tree in some degree recovered its verdure again that year, and 

 the next year made very good shoots, and so continued until this year. 

 ^ But this being a very dry summer, I perceived several of my trees in the 

 beginning of August look sickly, and particularly the tree formerly mentioned. 

 I made the same trial on them all, and found the bark sticking close to the 

 tree, with but little moisture between, and vast numbers of those small flies, 

 which had pierced the bark in numberless places. I ordered the earth about the 

 roots to be loosened as before, and about 1 hogsheads of water to be poured on 

 each ; then viewing them the next morning, I found the outside of the tree 

 almost covered with bees and wasps, and large black flesh flies, which were 

 all busy in sucking the juice or sap, which ran plentifully out at every hole, 

 made by the little flies in the bark, which was very glutinous, and sweet as 

 honey. I again examined the bark, and found it very moist between it and the 

 wood, and all those small flies either gone, or drowned in their new habitation 

 by the sudden rise of the sap: this tree recovered. 



On examining several trees, which looked sicklier than the rest, I found 

 that almost all greenness had left the bark, and there remained no moisture 

 between it and the wood ; but the bark stuck so close to the wood that it was 

 hardly to be parted; and throughout the whole tree the bark was pierced by the 

 ifinall flies, which, from the hole at which they entered, had made each of thera 

 a straight perpendicular channel from their entrance upwards, about 2 inches 

 long, or something more, very little, if at all, wider than just to move them- 

 selves straight forwards in it; for I observed that, when disturbed, they all came 

 out backwards. All along on each side this channel, as close to each other as 

 they well could, so as yet to be distinct, there were small channels running 

 horizontally from it, in every one of which, at the extremity, there was a. 

 maggot, in size just the width of the small channel, very lively, whitish, and 

 almost transparent. These trees, though well watered, received no benefit by 



