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Ahamus orhamulus is a structure functioning as, or in the form of, hooks or hooklets.
The terms are directly fromLatin, in whichhamus means "hook". The plural ishami.
Hamulus is thediminutive – hooklet or little hook. The plural ishamuli.
Adjectives arehamate andhamulate, as in "a hamulate wing-coupling", in which the wings ofcertain insects in flight are joined by hooking hamuli on one wing into folds on a matching wing.Hamulate can also mean "having hamuli". The termshamose,hamular,hamous andhamiform also have been used to mean "hooked", or "hook-shaped". Terms such ashamate[1] that do not indicate a diminutive usually refer particularly to a hook at the tip, whereas diminutive terms such ashamulose tend to imply that something is beset with small hooks.[2][3]
Invertebrate anatomy, a hamulus is a small, hook-shaped portion of a bone, or possibly of other hard tissue.
In human anatomy, examples include:[4]
Inarthropod morphology, hamuli are hooklets, usually in the form of projections of the surface of theexoskeleton. Hami might be actualevaginations of the whole thickness of the exoskeleton. The best-known examples are probably the row of hamuli on theanterior edge of themetathoracic (rear) wings ofHymenoptera such as the honeybee. The hooks attach to a fold on theposterior edge of themesothoracic (front) wings.
It is less widely realised that similar hamuli, though usually fewer, are used in wing coupling in theSternorrhyncha, thesuborder ofaphids andscale insects. In the Sternorrhyncha such wing coupling occurs particularly in the males of some species. The rear wings of that suborder frequently are reduced or absent, and in many species the lastvestige of the rear wing to persist is a futile little strap holding the hamuli, still hooking into the fold of the large front wings.
In thosespringtails (Collembola) that have a functionalfurcula, the underside of the thirdabdominal segment bears a hooked structure, variously called theretinaculum or hamula. It holds the furcula ready for release in times of emergency.[5]
The terms also are used in descriptive anatomy of some insect genitalia, such as hamuli in variousOdonata and "hamus" for the hooked part of the uncus in maleLepidoptera.[5]
Inbotany, such words largely refer to hooked bristles such as the hooks on therachilla ofUncinia, which attach the fruit to passing animals, or the similarly functioning hooks onBurdocks, well known as the alleged inspiration forVelcro.