Biomedical Engineering Reference
In-Depth Information
Class Hexapoda has two major subclasses: Entognatha and Ectognatha; hexa-
pods with enclosed mouthparts and hexapods with exposed mouthparts, respect-
ively. Class Insecta belongs to the Class Ectognatha (exposed mouthparts).
Members of Class Entognatha contain some of the most common organisms on
earth (e.g., Collembola, also known as springtails), but none infect humans [99].
All of the infectious members of Class Hexapoda belong to Class Insecta.
Despite its precise taxonomic definition, members of other animal classes
are often confused with members of Class Hexapoda. This is particularly
true for Class Chelicerata (Chapter 29), which contains spiders, mites, ticks,
and scorpions.
Hexapoda
Insecta
Hemiptera
Cimicoidea
Cimicidae
Cimicinae
*Cimex
Class Hemiptera, a subclass of Class Hexapoda, are the so-called “true
bugs.” They are distinguished from other insects by their mouth parts, which
are shaped as a proboscis and covered by a labial sheath. The mouth parts of
Class Hemiptera are designed for sucking. Class Hemiptera includes cicadas
and aphids. The triatome species that are vectors for Trypanosoma cruzi
(Euglenozoa, Chapter 17) are members of Class Hemiptera.
It is worth reminding readers that the word “bug” has no taxonomic
meaning, as it cannot be applied to any particular class of organisms. It is
meaningless to use the word “bug” to refer to any small crawling hairless
organism, as the organism may be an insect (Class Insecta), or a hexapod
that is not an insect (Class Entognatha), or a mite (Class Chelicerata) or a
pill bug (Class Crustacea).
Cimicidae are true bugs (i.e., Class Hemiptera). Bedbugs (Cimex lenticu-
laris) suck blood and produce an inflammatory response, but they are not a
true infection (they don't live in the skin), and they are not known to be car-
riers of other infectious agents. Bedbugs are included in this topic because
there is currently a bedbug epidemic in USA cities; bedbug enthusiasts
would be offended if this species were omitted.
Hexapoda
Phthiraptera
Anoplura
Pediculidae
*Pediculus
Pthiridae
*Phthirus
