INSECTS INJURIOUS TO THE ORANGE. 



409 



as seventy-five per cent, of the scales have been known to be 

 destroyed by it. The female fly pierces the scale and deposits 

 in it a single egg. When hatched, the larva feeds upon the 

 eggs and young of the bark-louse, and later upon the mother 

 also. When full grown, it is nearly one-sixth of an inch 

 long, broad, becoming narrower towards the head, of a trans- 

 parent white color tinged with blackish from the alimentary 

 canal showing through. The larva changes to a pupa within 

 the scale, which at first is white, but soon becomes darker in 

 color; the fly, on escaping, makes its exit through a round 

 hole which it cuts in the back of the scale. 



No. 261. — The Hemispherical Scale. 



Lecanium hemisphcerictim Targioni. 



Fig. 424 represents 

 this scale, of its natural 

 size, on orange leaves, 

 and a magnified one at 

 a. It varies in color 

 from light to dark brown, 

 and is occasionally tinged 

 with reddish when ma- 

 ture. In shape it is 

 hemispherical, with the 

 edges flattened, its form 

 varying somewhat in 

 difi^erent situations; upon 

 a rounded twig it be- 

 comes less hemispheri- 

 cal, more elongated, and 

 its flattened edges are 

 bent downwards, clasp- 

 ing the twig. 



The eggs are yellow- 

 ish white, smooth, and 

 shining. The newly- 



FiG. 424. 



