254 HEMIPTERA. 
especially those of the genera Parus and Regulus^ contain¬ 
ing the chickadee and our wrens, devour great quantities 
of these lice. I have also found that these insects are preyed 
upon by internal parasites, minute ichneumon-flies, and the 
holes (which are as small as if made with a fine needle), 
through which these little insects come forth, may be seen 
on the backs of a great many of the lice which have been 
destroyed by their intestine foes. 
The best application for the destruction of the lice is a 
wash made of two parts of soft soap and eight of water, 
with which is to be mixed lime enough to bring it to the 
consistence of thick whitewash. This is to he put upon the 
trunks and limbs of the trees with a brush, and as high as 
practicable, so as to cover the whole surface, and fill all the 
cracks in the bark. The proper time for washing over the 
trees is in the early part of June, when the insects are young 
and tender. These insects may also be killed by using in 
the same way a solution of two pounds of potash in seven 
quarts of water, or a pickle consisting of a quart of com¬ 
mon salt in two gallons of water. 
There has been found on the apple and pear tree another 
kind of bark-louee, which differs from the foregoing in many 
important particulars, and approaches nearest to a species 
inhabiting the aspen in Sweden, of which a description has 
been given by Dalman in tho “ Transactions of the Royal 
Academy of Sciences of Stockholm,” * for the year 1825, 
under the name of Coccus cryptogamus. This species is 
of the kind in which the body of the female is not large 
enough to cover her eggs, for the protection whereof another 
provision is made, consisting, in this species, of a kind of 
membranous shell, of the color and consistence almost of 
paper. In the autumn and throughout the winter, these 
insects are seen in a dormant state, and of two different 
forms and sizes on the bark of the trees. 
The larger ones measure less than a tenth of an inch 
in length, and have the form of a common oyster-shell, 
* Kongl. Vetenskaps Academ N;\'a Handlingar. 
