344 OF INSECTS, &c. 



immediately after heading, or cutting, or paring 

 off the diseased bark. 



A very destructive species of the Coccus tribe 

 has lately done incredible damage to the Apple- 

 trees in the nurseries and gardens in the neigh- 

 bourhood of London. Some Nurserymen have 

 lost several thousand Apple-trees in one year. 

 These insects attach themselves to the bark by 

 their suckers, and, by feeding on the juices of the 

 tree, rob it of its nourishment. Such trees as are 

 infested with them have a sickly appearance. J 

 am happy, however, in being able to say, that I 

 have nearly extirpated them from His Majesty's 

 gardens at Kensington : but, as our neighbours do 

 not pay the same attention to their trees as we do 

 to ours, the insects frequently emigrate to us ; this 

 obliges me to be very attentive to their first 

 appeal ance ; and, as I take the earliest opportunity 

 of destroying them, the trees suffer very little from 

 their depredations. 



These insects make their nests generally where 

 branches have been cut off, or in hollow places, 

 wher ihe canker has eaten holes in the trees. 

 Their first appearance is like a white down ; on 

 touching, or rubbing them, they tinge the fingers 

 of a crimson colour, like cochineal. If suffered to 

 remain long on trees, they take wing, like Aphides, 

 The method that I have followed for these ten 

 years to destroy them is as follows : 



I rub the places where their nests are with an 



