LIBRARY

68
COLLEGE ENTOMOLOGY
contiguous or approximate dorsally, and the ocelli are elongate or arranged in
groups in front of the compound eyes. They inhabit grassy and wooded areas,
some species living in wet and others in dry places in the grass, among leaves,
in dead wood, under bark and stones, among roots in the soil, or on rocks covered
with lichens, while others are tenants in caves and small holes in the ground
and a few inhabit termite nests. Ordinarily they move rather slowly but when
c F
FIG. 27. Characters of TI-IYSANURA. A, Atciura icPislnoidea Folsom (after Folsom);
S, a scale of Lepisma; C, Nicoletia pllytofJ/zila Gervais (after Nicolet); n, ventral aspect of
abdomen; E, mesothol'acic leg; and F, body scale of Machilis maritima Leach (after Oudemans.)
disturbed jump with great agility. Their food appears to be various forms of
dried or decayed vegetation. No species are recorded as pests of living plants or
of the household. The individuals are best collected in an empty shell vial by
placing the open ends over the insects, allowing them to jump into it, and immediately
transferring the specimens to a boUle of 80 per cent alcohol where
they may be kept until ready [or study. Permanent mounts may be made in
balsam, euparal, or other media on grass slides; or freshly killed specimens may
be preserved in good condition in riker mounts if care is taken in handling them.
The latter method is especially desirable for laboratory studies in general entomology.
There are approximately 30 genera, 150 species, and three subfamilies known.
They are. most abundant in the Palrearctic region, where nearly half of the
species have been collected. The other regions follow in order of number of
species: Nearctic, Indo-Malaysian, Neotropical, Ethiopian, and other regions