INSECT PESTS AND DISEASES. 167 



The insect is closely allied to the aphis, but differs in 

 the absence of secreting or honey glands on the abdomen, 

 and by its being more or less covered with a mealy dust, 

 while the hinder parts and the sides of the body are 

 furnished with a tuft of white woolly or cottony matter. 

 During the early part of summer, wingless females bring 

 forth young like themselves, at a prodigious and alarming 

 rate, crowding the twigs, branches, and various parts of 



FIG. 4.S. AMERIQAN BLIGHT. 



the trunk of the tree with cottony masses, as seen in the 

 engraving, that scarcely hide the leaden-coloured and 

 brown insects beneath. Later on, winged females are 

 produced, which spread the pest from tree to tree, and into 

 fresh and previously unaffected orchards. Winged males,, 

 and winged egg-laying females are developed in autumn, 

 and the latter lay their eggs in crevices of the bark 

 towards the base of the tree, and on suckers. The perfect 



