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Moths - Glossary

Terms used in moth descriptions. As far as possible this website avoids the use of scientific terms where accepted English terms are unambiguous. However many are included in this list because other books and websites use them.

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abdomen

abundance



adult

antemedian

antenna


apex

basal

Base

Bradley and Fletcher number (BF)



cell

central cell


central spot

cilia

common

confusion species

costa

crossband

crossline

dimorphic

discal cell

discal spot

distal


dorsum

fascia  

flight period


forewing

forewing length

generation

geometer

Hindwing

instar



kidney mark


larva

leading edge

Lepidoptera



local


macro moth



median


micro moth



migrant


noctuid

orbicular stigma


outer edge

oval mark


palp



postmedian


proximal


pupa


reniform stigma


scale


scale tuft


scarce


status













stigma

subbasal

subfalcate

subterminal


terminal


termen

thorax

tip

tornus

tortrix

trailing corner

trailing edge

underwing

vein

widespread


wing length


wingspan

The main length of the body of an adult moth after the thorax

The relative occurrence of a species. Often measured using the so-called ACFOR scale by allocating to each species an abundance of : ABUNDANT, COMMON, FREQUENT, OCCASIONAL or RARE
See also definition of Status

The winged stage in the life cycle of a moth

A crossline or crossband nearer the base than the centre of the wing

One of two long sensory appendages on the head of a moth. Often the male moth has a wider, more feathery antenna than the female - probably to sense the presence of female pheromones.

The tip of a wing between the leading edge and the trailing edge

At the base of the wing

Where the wing is attached to the thorax

Each British species of butterfly and moths has been allocated a number. These numbers are derived from "A Recorder's Log Book or Label List of British Butterflies and Moths" by J.D. Bradley and D.S. Fletcher.
In the future we may change to a decimal-style system derived from  "A checklist of the Lepidoptera of the British Isles" by Agassiz, D.J.L., Beavan, S.D. & Heckford R.J. (2013) but will use BF numbers for the moment.

An area of a wing enclosed by veins

=discal cell A cell near the centre of the wing which varies in shape from species to species and is useful in identification

=Discal spot On some moths, such as pugs, the central cell is a relatively small dark spot.

Fine hairs - particularly in a fringe around the edge of a wing.

The status of a moth that is widespread and frequent - but see status

Another species so similar to the moth being studied that they are difficult to tell apart.

The leading edge of the wing when the moth is in flight

= fascia a band of colour across the wing from leading edge to trailing edge

a line of colour across the wing from leading edge to trailing edge

The male and female of a species are quite different in any or all of shape, size and wing patterns.

 A cell near the centre of the wing which varies in shape from species to species and is useful in identification

= central spot or discal spot - a spot or mark on the wing  

Nearer to the outer edge of the wing than the feature described - e.g. “there is a black spot distal of the central crossband”

The trailing edge of a wing when the moth is in flight

=crossband A broad band of colour across the wing from leading edge to trailing edge

The months when the adult moth is likely to be seen. Some moths have two or three generations and so have more than one flight period. Flight periods may be different in different parts of the country.

The leading wing when the moth is in flight - it is above or overlapping the hindwing when the moth is at rest.

The distance from the base of the forewing to the tip or apex (in mm)

 Some moths may go through the complete life cycle from egg, larva and pupa to adult twice or even three times in a year. Each life cycle is a separate generation.

A moth of the family Geomitridae- a large family whose larvae move by 'looping'

The wing which is behind when the moth is flying and often held underneath when the moth is resting - particularly in noctuids

A developmental stage in the life of an insect where one stage casts off the outer skin to reveal the next stage.
In the case of moths there are usually 4 or 5 such stages in the development of the larva, followed by the pupa or chrysalis, which is the final stage before the adult moth emerges.

=reniform stigma A kidney-shaped mark nearer to the outer edge of the wing than the oval mark. Important in identifying Noctuid moths.

The caterpillar - the stage after the egg

=costa - the edge of the wing which is in front when the moth is flying

Butterflies and moths together form a large group of insects defined as the order Lepidoptera. They are distinguished by the fact that colouring on their wings is made of scales
 (from the Greek lepidos - a scale - and pteron - a wing).

Refers to a species which is only found in some areas or some habitats. Used on its own 'local' often implies that the species is not common - though a species can be 'locally common'.

A non-scientific term used to describe a large grouping of moth families including the Geometers, Noctuids, Hawk moths and others - most macro moths are larger than most micro moths. There are about 900 British species of macro moths, including about 400 noctuids and over 300 geometers.

Describes a position on the wing midway between the base and the outer edge. Used to describe the position of a crossline or a crossband.

A non-scientific term to describe all the moth families which have not been included among the macro moths. Many, but not all, micro moths are smaller and more primitive than most macro moths. There are about 1600 British species of micro moths

A species which does not normally over-winter in this country but flies here from abroad each year.
Each year billions of moths use upper air currents to fly here - mainly from Southern Europe.

A moth of the large family Noctuidae

=oval mark -  A round or oval mark near the centre of the forewing on some moths, particularly Noctuids, and helpful in identifying species.

=termen The outer edge of the wing of moth when it is in flight i.e. the edge of the wing farthest from its base.

= orbicular stigma A round or oval mark near the centre of the forewing on some moths, particularly Noctuids, and helpful in identifying species.

One of two small appendages arising from the mouth of a moth - probably used for sensing food.
Occasionally two species can be separated by studying the palps.


The outer side of the centre of the wing, away from the base. Used to describe the position of a crossline or a crossband as near to the centre of the wing but towards the outer edge.

Nearer to the base of the wing than the feature described - e.g. there is a black spot proximal of the central crossband.

The third main stage in the life cycle of a moth. So the stages in order are ova (egg), larva (caterpillar), pupa (chrysalis), adult.

=kidney mark - a large mark towards the outer edge of the forewing, which is often kidney-shaped and often bordered by a ring. Often important in identifying species of noctuid.

The wings of all butterflies and moths are covered in tiny scales. This feature is a distinguishing character of this order of insects - the name Lepidoptera means ‘scale-winged’.
 
A group of scales standing out from the surface of the wing. These tufts often help in identification - e.g. in a number of Tortrix moths
 
Refers to a moth species which is rare and seldom found. If a species is subject of concern it is regarded as Nationally scarce.

short for National Status

Each species of moth resident in the United Kingdom has been given a status showing how common or rare it is based on the National Record database.

The Joint Nature Conservation Committee has coordinated efforts and has produced a database of all species of plant or animal which are rare, vulnerable or endangered - including nearly 400 moth species.

The criteria are based on the number of 10km squares on an OS map a species has been recorded in :-

    1 to 15 squares :- In the Red List of vulnerable or endangered species

    16-100 squares :- Nationally Scarce

For less rare species the status is often given as -

    101 - 300 squares :- Local

    301 or more squares :- Common

As there are over 3000 10km squares in the United Kingdom the term 'common' by this definition covers some species that are not normally seen. Compare with definition of Abundance.

A spot or mark on the wing of a distinctive colour. See reniform stigma and orbicular stigma

towards the base of the wing but away from it.

Nearly sickle-shaped - usually refers to a wing having a hook tip.

Towards the outer edge of the wing but away from it. E.g. If there are two crosslines or crossbands near the outer edge of the wing the subterminal one is nearer the centre of the wing than the terminal one.

The area near to the outer edge of the wing. E.g. A terminal crossline is the last crossline before the outer edge of the wing.

The outer edge of the wing - between the tip and the trailing corner.

The section of the body between the head and the abdomen, which wings and legs are attached to.

The apex of a wing

The trailing corner of the wing - the corner between the outer and trailing edges of the wing.

A moth of the large family Tortricidae

= tornus The trailing corner of the wing

= dorsum  The trailing edge of a wing when the moth is in flight

The hindwing. The term is particularly used for noctuids and other moths where the hindwing is under the forewing when at rest.

One of the struts across the wing which strengthen it. Often obscured by the scales, but clearly marked in some species.

Refers to a species which is found all over the country or region - the term does not necessarily imply it is common or abundant.

The distance from the base of the forewing to the tip of the wing (apex). Usually measured in millimetres. For a live moth it is easier to measure than the wingspan.

The distance from forewing tip to forewing tip of a moth with its wings fully extended - as in flight. Usually measured in millimetres.