105 



ash and other trees have been mistaken, even by 

 philosophers, for lichens, &c. 



The little animals sticking to the bark of the apple- 

 trees are so similar to mussel-shells, that GeofFroy 

 called them " Le Kermes en ecaille de moule," but 

 instead of giving them an appropriate scientific name, 

 he designated them as the Chermes arborum-linearis. 

 Gmelin has in some measure supplied the deficiency, 

 by describing them under the name of Coccus con- 

 chiformis ; but if he had applied the term of Mytili- 

 formis, mussel-shaped, it would have been more signi- 

 ficant. These scales do not lie in one direction, as 

 others generally do, with their heads downward, for 

 some of the apple-tree scales are placed vertically, 

 others obliquely, and many have a transverse direction 

 (fig. 1) ; and sometimes they are crowded together in 

 immense multitudes in every possible position, even 

 lying one over another. The scales are hard, dark, 

 and shining ; they are exceedingly like a minute mus- 

 sel-shell, but rather more elongated; they are slightly 

 curved, transversely wrinkled, rounded at the tail, 

 and attenuated at the head, which is semi-cylindric, 

 less opaque, and of a rusty colour (fig. 2). These 

 adhere firmly to the bark, having the margins broad 

 beneath and woolly (fig. 3), and when dislodged, the 

 space they had covered appears white. Within the 

 shell is found a fleshy-green female, occupying part 

 of the cavity towards the tapering extremity (fig. 4), 



