— 13 — 
THE OYSTER-SHELL BARK- LOUSE. {M ijtUasjtis pornormn 
Bouse} ie>) 
This scale is common in the eastern and northeastern 
U. S. and in Canada. It is an enemy of the apple-tree of 
considerable importance and will doubtless be found in some 
of the orchards of this State at no distant date, though it 
has not yet been reported in Colorado. It is a very easy 
pest to overlook. The scales are about one-eighth of an 
inch in length, a little curved like an oyster shell, and the 
color is almost exactly that of the bark of an apple tree. 
They occur chiefly upon the bark and, when abundant, weak- 
en the vigor of the tree. or even cause it to die. The scales 
are very well shown in Fig. g. During the fall, winter and 
early spring, these scales have eggs beneath them. About 
the last of May the eggs hatch and the minute yellowish 
lice travel about over the tree, find suitable locations, insert 
their beaks, feed and grow, forming over themselves the 
peculiar scale under which they deposit eggs and die by the 
last of August or early in September. 
Fig. 9.- -Oyster-shell Bark-Louse :Z a, female scale from below, showing 
greatly enlarged; b, the same from 'above; c, female scales on twig natural 
size; e, male scales, natural size; d, male scale enlarged. (Howard, Yearbook, U. 
S. Dep. of Agr., 1894.) 
Remedies — The same as for the preceding species. 
