e near relationship of the
Thysanura to the Neuroptera.

[Illustration: 164. 165. 166. 167.

Development of a Poduran.]

The earliest stage observed was at the time of the appearance of the
primitive band (Fig. 164, _a_, _b_, folding of the primitive band; _c_,
the dotted line crosses the primitive band, and terminates in a large
yolk granule) which surrounds the egg as in the Caddis flies. Soon
after, the primitive segments appear (Fig. 165; 1, antennae; 2,
mandibles; 3, maxillae; the labium was not seen; 5-7, legs; _c_, yolk
surrounded by the primitive band) and seem to originate just as in the
Caddis flies. Figure 166 is a front view of the embryo shortly before
it is hatched; figure 167, side view of the same, the figures as in Fig.
165; _sp_, spring; _l_, labrum. The labrum or upper lip, and the clypeus
are large and as distinct as in the embryos of other insects, a fact to
which we shall allude again. The large three-jointed spring is now well
developed, and the inference is drawn that it represents a pair of true
abdominal legs. The embryo when about to hatch throws off the egg-shell
and amnion in a few seconds. The larva is perfectly white and is very
active in its movements, running over the damp, inner surface of the
bark. It is a little over a hundredth of an inch in length, and differs
from the adult in being shorter and thicker, with the spring very short
and stout. In fact the larva assumes the form of the lower genera of the
family, such as Achorutes and Lipura, the adult more closely resembling
Degeeria. The larva after its first moult retains its early clumsy form,
and is still white. After a second moult it becomes purplish, and much
more slender, as in the adult. The eggs are laid and the young hatched
apparently within a period of from six to ten days.

Returning to the stage indicated by figures 166 and 167, I am induced to
quote some remarks published in the Memoirs of the Peabody Academy of
Science, No. 2, p. 18, which seem to support the view that these insects
are offshoots from the Neuroptera.

"The front of the head is so entirely different from what it is in the
adult, that certain points demand our attention. It is evident that at
this period the development of the insect has gone on in all important
particulars much as in other insects, especially the Neuropterous
Mystacides as described by Zaddach. The head is longer vertically than
horizontally, the frontal, or clypeal region is broa