LIBRARY

PROTURA 61
ern North America was collected by Ewing in decaying leaves in the Yosemite
Valley, Calif., April 15, 1927, and described as Eosentomon yosemitensis by
Ewing the same year. In recent years many species have been discovered in
North America, especially [rom Maryland, New York, Pennsylvania, Virginia,
North Carolina, Illinois, Arkansas, Louisiana, Florida, Texas, Iowa, California,
and Mexico. In California a second species, Acerentulus californicus, was collected
in a canyon near Claremont and described in 1929 by W. A. Hilton, who
has discovered proturans in many parts of southern California. Ewing has
described most of the American species. So far practically nothing is known
concerning the life histories and food habits of these primitive insects. Those
collected have been found in damp situations under leaves, bark, and stones, in
rotten wood, decaying vegetation, turf, and humus soils.
Proturans are peculiar in that they walk only on the middle and hind legs and
hold the fore pair in front of and above the head as tactile organs, not unlike
some of the ARACHNIDA.
They have been placed in a separate class, MYRIENTOMATA Berlesc, or
PROTURA (Silvestri) by some entomologists because of certain affinities with
CHILOPODA and SYMPHYLA, but mosi modern authors agree that they
are sufficiently closely related to insects to warrant their inclusion in the
INSECTA.
Noninsect Characters
1. No antenn::e.
2. Position of the genital aperture behind
the penultimate segment.
3. Anamorphosis - the acquisition of
three abdominal segments after birth.
4. Reduction or loss of tracheal system.
Insect Characters
1. Differentiated thorax.
2. Three pairs of legs.
3. Mouth parts very similar to those III
the COLLEMBOLA.
There are approximately 62 species described from various parts of the world.
of which 23 are Nearctic, two Neotropical, 27 Palrearctic, two Oriental, one
Ethiopian, and six Australian.
KEY TO FAMILIES 1
(After Ewing, 1940)
1. Trachere present; a pair of spiracles on the mesothorax and also on the
metathorax:; all vestigial abdominal appendages two-segmented; abdominal
segment VIII without pectines . EOSENTOMIDlE p. 62
Trachere and spiracles abgent; pectines on abdominal segment III onesegmented;
abdominal segment VIII with a pair of pectines . 2
2. Abdominal terga each with one or three transverse sutures and a pair of
laterotergites; abdominal segments with two complete transverse
rows of dorsal setre; abdominal segment VIII with obvious pectines
ACERENTOMIDlE p. 63
1 The superfamily and family endings oidea and idre are derived from the Greek flaos.
meaning something seen, a form. shape. figure. species, kind.