SCALE-INSECTS, BARK-LICE, MEALY-BUGS. 239 
Chionaspis pinifolie Fitch. (The White Pine-scale). 
This insect is also becoming very numerous, and in some 
places, especially upon pines growing in the yards as ornamental 
trees, they become decidedly injurious. The insect forms white 
scales upon the leaves of this tree, exhausting the sap, in conse- 
quence of which the foliage becomes sickly and yellow. The 
species is illustrated in Fig. 191. 
To the genus Mytilaspis belong a number of very injurious 
scale-insects, one of which is described below. 
Fig. 192 a.—Mytilaspis piomorum Bouche: a, male; b, its tarsus; c, young larva; 
d, its antenna; e, female—all greatly enlarged. After Div. of Entomology, 
Dep. of Agriculture. 
Mytilaspis pomorwm Bouche. (The Oyster-shell Bark-louse of 
the Apple). 
This species is very destructive, and is rapidly spreading in 
our orchards, where it not alone injures the apple, but also a 
number of other trees. In one case it was found in such num- 
bers upon the twigs of imported horse-chestnut trees, that it had 
caused their death. The insect well deserves the popular name 
it has received, since the shape of the scale resembles that of one 
