238 SCALE-INSECTS, BARK-LICE, MEALY-BUGS. 
of the same kind as come in contact with it. Fig. 189, Plate 
xv). 
Chionaspis americana Johnson. (The Elm-tree White-scale). 
Many of the fine elms in the vicinity of St. Paul and Minne- 
apolis are infested with small white scales closely resembling those . 
on the cottonwood, but less conspicuous, as the bark of the elm 
is spotted with white, and therefore better adapted to conceal 
them (Fig. 190). They are present on both the trunks and 
Fig. 192.—Mytilaspis pomorum Bouche: a, female scale, from beneath, filled with 
eggs; b, same from above; c, twig infested by female scales; d, male scale, and 
a twig infested therewith. After Div. of Entomology, Dep. of Agriculture. 
twigs. The female scale is white and pear-shaped, while the 
male is smaller and more slender, and has a slight longitudinal 
ridge. This scale is not known to be destructive at present, but 
notice is given so that it may be recognized should it ever be- 
come so. 
