ring.
During a mild December, they may be found in abundance under sticks and
stones, even in situations so far north as Salem, Mass.

[Illustration: 156. Smynthurus.]

The body of the Poduras is rather short and thick, most so in Smynthurus
(Fig. 156), and becoming long and slender in Tomocerus and Isotoma. The
segments are inclined to be of unequal size, the prothoracic ring
sometimes becoming almost obsolete, and some of the abdominal rings are
much smaller than others; while in Lipura and Anura, the lowest forms of
the group, the segments are all much alike in size.

The head is in form much like that of certain larvae of Neuroptera and of
Forficula, an Orthopterous insect. The basal half of the head is marked
off from the eye-bearing piece (epicranium) by a V-shaped suture[10]
(Fig. 157, head of Degeeria; compare also the head of the larva of
Forficula, Fig. 158, in which the suture is the same), and the insertion
of the antennae is removed far down the front, near the mouth, the
clypeus being very short; this piece, so large and prominent in the
higher insects, is not distinctly separated by suture from the
surrounding parts of the head, thus affording one of the best
distinctive characters of the Poduridae. The eyes are situated on top of
the head just behind the antennae, and are simple, consisting of a group
of from five to eight or ten united into a mass in Smynthurus, but
separated in the Poduridae (see Fig. 176, _e_, eye of Anurida). The
antennae are usually four-jointed, and vary in length in the different
genera.

[Illustration: 157. Head of Degeeria.]

[Illustration: 158. Larva of Forficula.]

The mouth-parts are very difficult to make out, but by soaking the
insect in potash for twenty-four hours, thus rendering the body
transparent, they can be satisfactorily observed. They are constructed
on the same general type as the mouth-parts of the Neuroptera,
Orthoptera and Coleoptera, and except in being degraded, and with
certain parts obsolete, they do not essentially differ.[11] On observing
the living Podura, the mouth seems a simple ring, with a minute labrum
and groups of hairs and spinules, which the observer, partly by
guess-work, can identify as jaws and maxillae, and labium. But in
studying the parts rendered transparent, we can identify the different
appendages. Figure 159 shows the common Tomocerus plumbeus greatly
enlarged (Fig. 160, seen from above), and as the mouth-parts of the
whole gr