252 
IlEMIPTERA. 
more, till nothing is left but the dry outer convex skin, and 
the insect perishes on the spot. Sometimes 
the insect’s body is not large enough to cover 
all her eggs, in which case she beds them 
in a considerable quantity of the down that 
issues from, the under or hinder part of her 
body (Fig. 95). There are several broods 
of some species in the year ; of the bark -louse 
of the apple-tree at least two are produced 
in one season. It is probable that the insects 
of the second or last brood pair in the au- 
tumn, after which the males die, but the 
females survive the winter, and lay their 
eggs in the following spring. 
Young apple-trees, and the extremities of 
the limbs of older trees, are very much subject to the attacks 
of a small species of bark-louse. The limbs and smooth 
parts of the trunks are sometimes completely covered with 
these insects, and present a very singularly wrinkled and 
rough appearance from the bodies which are crowded closely 
together. In the winter these insects are torpid, and ap- 
parently dead. They measure about one tenth of an inch in 
length, are of an oblong oval shape, gradually decreasing to 
a point at one end, and are of a brownish color vex-y near to 
that of the bark of the tree. These 
insects resemble in shape one which 
was described by Rdaumur * in 1738, 
S who found it on the elm in France, 
and Geoffroy named the insect Coc- 
cus arborum linearis , while Gmelin 
called it conchiformis (Fig. 96). This, 
or one much like it, is very abundant 
upon apple-trees in England, as we 
learn from Dr. Shaw f and Mr. 
* M&noires, Vol. IV. p. 69, plate 6, figs. 5, 6, 7. 
t General Zoology, Vol. VI. Part I. p. 196. 
