Editing Cercus (section)

==Morphology and functions==
Most cerci are segmented and jointed, or filiform (threadlike), but some take very different forms. Some [[Diplura]], in particular ''Japyx'' species, have large, stout forcipate (pincer-like) cerci that they use in capturing their prey.<ref name= "isbn0-412-61390-5">{{cite book |author1=Richards, O. W. |author2=Davies, R.G. |title=Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology |publisher=Springer |location=Berlin |year=1977 |isbn=0-412-61390-5 }}{{pn|date=June 2021}}</ref>

The [[Dermaptera]], or [[earwig]]s, are well known for the forcipate cerci that most of them bear, though species in the suborders [[Arixeniina]] and [[Hemimerina]] do not. It is not clear how many of the Dermaptera use their cerci for anything but defense, but some definitely feed on prey caught with the cerci, much as the [[Japygidae]] do.<ref name= "isbn0-412-61390-5"/>

[[Cricket (insect)|Crickets]] have particularly long cerci while other insects have cerci that are too small to be noticeable. However, it is not always obvious that small cerci are without function; they are rich in sensory cells and may be of importance in guiding copulation and [[ovipositor|oviposition]].
[[File:Gryllus pennsylvanicus cercus mosbo6.jpg|thumb|Cercus of an adult female ''[[Gryllus pennsylvanicus]]'']]
In groups such as crickets and [[Cockroach|cockroaches]], cerci play important sensory roles. They have been shown to be sensitive to puffs of air and low-frequency vibration, and thus trigger anti-predatory responses such as escape in response to certain predators. In [[Gryllinae|field crickets]], the range of frequency detection by the cerci spans from [[Infrasound|infrasonic sound]] to nearly 1 kHz. In crickets, higher-frequency sound such as [[stridulation]] and [[Ultrasound|ultrasonic]] bat calls are picked up by a separate [[tympanal organ]], not the cerci.<ref>{{cite journal |last1=Hoy |first1=Ronald R. |last2=Pollack |first2=Gerald S. |last3=Moiseff |first3=Andrew |title=Species-Recognition in the Field Cricket, Teleogryllus oceanicus: Behavioral and Neural Mechanisms |journal=American Zoologist |date=1982 |volume=22 |issue=3 |pages=597–607 |doi=10.1093/icb/22.3.597 |jstor=3882581 |doi-access=free }}</ref>

{{anchor|terminal filament}}Some [[Hexapoda|hexapods]] such as [[mayflies]], silverfish and [[Diplura|diplurans]] possess an accompanying third central tail filament which extends from the tip of the [[abdomen]]. This is referred to as the ''terminal filament'' and is not regarded as a cercus.<ref name="UMN"/>

[[Aphid]]s have tube-like [[cornicle]]s or siphunculi that are sometimes mistaken for cerci but are not [[Morphology (biology)|morphologically]] related to cerci.