Agriculture Reference
In-Depth Information
Superfamily DEMODICOIDEA
Superfamily
TROMBIDIOIDEA
13. Family DEMODICIDAE
14. Family TROMBIDIIDAE
Minute (0.1-0.4mm long), vermiform, distinctly
annulated, almost colourless mites; legs very
short and stumpy, located anteriorly; chelicerae
stylet-like. The mites inhabit the hair follicles of
mammals, including those of man.
EXAMPLES:
Demodex bovis
(cattle follicle
mite),
Dermodex equi
(horse follicle mite).
Relatively large (2-3 mm long), plump, spider-
like mites with a velvet-like appearance, owing
to the dense coat of setae on the body and legs
(Fig. 175).
Predacious on various insects.
EXAMPLE:
Allothrombium
fuliginosum
(red
velvet mite).
ORDER ASTIGMATA
Weakly sclerotized, whitish or pale brown mites
without stigmata or tracheae; pedipalps small, 2-
segmented and inconspicuous; chelicerae dis-
tinctly chelate; idiosoma usually oval and with no
obvious segmentation, although sometimes with
a slight groove between the propodosoma and
hysterosoma; ocelli usually absent. Terrestrial
mites, including parasitic, predatory and phyto-
phagous species. Adults 0.2-1.5 mm long.
claw. The only known species is predacious on
scale insects.
EXAMPLE:
Hemisarcoptes malus
(mussel scale
predatory mite).
3. Family SARCOPTIDAE
Small, globular mites with very short, stumpy
legs; body distinctly striated transversely but
1. Family ACARIDAE
(p. 269
et seq.)
Pearly-white or translucent, smooth-bodied
mites; some body setae often very long;
propodosoma and hysterosoma separated by a
sejugal furrow
(Fig. 176).
Often associated with
damp, mouldy or rotting plant tissue and breed-
ing amongst stored farm products.
EXAMPLES:
Acarus siro
(flour mite),
Gohieria
fusca
(brown flour mite),
Rhizoglyphus callae
and
R. robini
(bulb mites),
Tyrophagus
neiswanderi
(cucumber mite).
2. Family HEMISARCOPTIDAE
Small (0.2-0.3mm long), smooth, shiny, egg-
shaped mites, with a propodosomal shield
and short, robust legs; propodosoma and
hysterosoma clearly demarcated by a sejugal
furrow; each leg terminates in a trumpet-like
pulvillus but there is no tarsal or ambulacral
Fig.
176
A fungal mite,
Tyrophagus
sp.- family
Acaridae (xlOO).
