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two varieties of pine above mentioned. On the narrow leafet of 
the White Pine, the scale—or I should specify, for reasons which 
will appear hereafter—th q female scale, has a slender and linear 
form, exactly corresponding to the width of the leaf on which it is 
moulded ; but on the broader leaf of the Scotch Pine, where it has 
space to expand, it may be supposed to assume its normal shape. 
It here often appears almost in the form of an elongated triangle 
with its terminal or shorter side rounded. Its generic tendency 
to the muscle shape is perceptible only in one of the long sides 
being nearly straight and the other a little more arched. 
Upon a more critical examination, these scales are seen to be 
composed of three parts, one behind the other, gradually increas¬ 
ing in size, and thus marking the successive stages of the insect’s 
growth. Mr. Walsh designated these parts, respectively, as the 
larval scale, the medial scale, and the anal sack. The French 
authors call the large terminal portion the buckler or shield, but 
to avoid unnecessary changes I shall, in the present article, adopt 
Mr. Walsh’s names. Besides, the term anal sack expresses more 
accurately the composition of this part, it being turned under at 
its edges so as to inclose the insect and its eggs. Bat this inferior 
lamina is very thin, and being adherent to the surface of the leaf 
it is necessarily ruptured in raising the scale. 
The larval scale is of a pale, transparent amber color, and a 
flattened, oval form, slightly elevated or carinated along the mid¬ 
dle, with transverse furrows on each side, indicating imperfectly 
that division into rings or segments which characterizes all the 
annulose animals. The larval scale, as its name implies, is evi¬ 
dently the moulted skin or envelope of the insect in its primitive 
or larval state. In retreating from it, the insect leaves all its 
members attached to it. 
The small, and scarcely more than rudimental legs, and the 
slender anal filaments become obliterated and indistinguishable 
as soon as the larva is fixed; but the antennse remain and can 
generally be seen attached to the anterior extremity of the scale 
after the lapse of a year, and after the insect beneath has passed 
through all the phases of its existence. 
In leaving its larval envelope, the insect retreats a little upon 
the leaf, and at the same time becomes clothed with a new integu¬ 
ment, closely resembling the former, but a tint darker colored, 
