[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

CHAPTER 13 The Arthropods
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Phylum
Arthropoda
Class
Chilopoda
Class
Pentastomida
Class
Arachnida
Class
Crustacea
Organisms
Centipedes
Tongueworms
Ticks*
Mites*
Spiders*
Scorpions*
Crabs
Crayfish
Copepods
Flies*
Class
Insecta
Mosquitoes*
Lice*
Fleas*
Bugs*
*Discussed in chapter.
FIGURE 13-1 Arthropod classification.
Hard tick
Soft tick
Capitulum
Scutum
Dorsal side
Dorsal side
FIGURE 13-2 Comparison of adult hard and soft ticks.
structure is visible on the dorsal side of hard ticks,
but it is invisible on the dorsal side of soft ticks
because of its ventral positioning. Located posterior
to the capitulum on hard ticks is a dorsal hard
shield known as a scutum. Soft ticks lack this structure
and have, instead, a leathery outer surface. The
typical tick ranges in size from 6 to 8 mm long.
Life Cycle Notes
Ticks are ectoparasites whose life cycles contain
four morphologic stages—eggs, larvae (defined as
juvenile stage), nymphs (defined as a developmental
stage that resembles that of an adult), and
adults of separate sexes. The life cycle typical