It lays eggs under its body, and thus also under
the protecting wax scale, and dies. From the eggs hatch active little
larval "scale bugs," with eyes and feelers, and six legs. They crawl from
under the wax scale and roam about over the orange tree. Finally, they
settle down, thrusting their sucking beak into the plant tissue, and cast
their skin. The females lose at this molt their legs and eyes and feelers.
Each becomes a mere motionless sack capable only of sucking up sap and
laying eggs. The young males, however, lose their sucking beak and can no
longer take food, but they gain a pair of wings and an additional pair of
eyes. They fly about and fertilize the sacklike females, which then molt
again and secrete the thin wax scale over them.
Throughout the animal kingdom loss of the need of movement is followed by
the loss of the power to move and of all structures related
to it.
--Jordon and Kellogg: _Animal Life_.
Has the principle of unity been observed in the above selection; that is,
of the many things that might be told about a sea squirt, a barnacle, or a
scale bug, have the authors selected only those which serve to illustrate
degeneration through quiescence?
Instead of one generalization supported by a series of facts to
each of which a paragraph is given, we may have several subordinate
generalizations relating to the subject of the theme. Each of these
subordinate generalizations may become the topic statement of a paragraph
which is further developed by giving specific instances or by some other
method of paragraph development.
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