The Families of British Microlepidoptera

The Families of British Microlepidoptera

The account of the families of British (and Irish) Microlepidoptera that follows gives a summary of the main easily visible characters of each family as delimited in Moths and Butterflies of Great Britain and Ireland (Vol. 1, 1976; Vol. 2, 1985; Vol. 3, 1996 and Vol. 4, 2002). Since 1976 there have been extensive changes in the family level classification of Lepidoptera, some now generally accepted, others more controversial. These changes are only recognised here if they were adopted in the relevant volume of MBGBI.

The following `honorary macro’ families appear in Skinner’s Moths of the British Isles: Hepialidae, Cossidae, Zygaenidae, Limacodidae, Sesiidae. Only the remaining 38 micro families which have been or are expected to be treated in MBGBI Volumes 1-6 are considered here. This is a total of 1557 species, of which 1361 (87%) belong to only 11 families. In theory it should be easy to familiarise oneself with the general `jizz’ of 11 families, but some of the families are very diverse. The remaining 27 families include some of the most abundant British moths, such as Anthophila fabriciana (Choreutidae) and Glyphipterix simpliciella (Glyphipterigidae).

It was hoped that a key to the families of Microlepidoptera could be produced, without resorting to `technical‘ characters (ocelli, wing venation, tympanal organs, abdominal re-inforcement and ornamentation, genitalia etc) which are not visible with a hand lens. Such a key may be possible, but is not something that can be produced quickly. The following account is produced as an interim measure. After a key has been produced, it should remain useful for checking that a family that has been reached through the key is probably the correct one.

Every attempt has been made to keep the number of technical terms down, but they can be so much clearer and more concise than non-technical descriptions.

The mouth parts consist of two pairs of palps, the outer (and usually larger pair) are the labial palps with three segments, the first very short; the inner pair are the maxillary palps, usually smaller and sometimes much reduced, but when well developed usually 5 or 6-segmented, sometimes folded. In most families there is a tongue, but the most primitive have mandibles, functional or rudimentary.

The antennae have an enlarged basal segment, the scape, and a thread-like many segmented flagellum. The scape may be clothed with a broad cloak of scales forming an eye cap, or it may have a few downward projecting bristle-like scales forming a pecten. This pecten has nothing to do with pectinate antennae in which the segments of the flagellum have lateral outgrowths that together form a comb or bipectinate antennae with a double comb. Ciliate antennae have long hairs on each segment.

The head is usually described as being rough or smooth-scaled according to the direction of the scales on the crown of the head and the face. This is confusing as there are more than two types involved. The following terms are used here: spiky, with long erect bristle-like scales giving the effect of a bottle-brush; erect, with a dense mat of erect scales, resembling a carpet; raised, with scales that rise from the head but are directed forwards and downwards; smooth, with appressed scales. Frequently the face is smooth, but the crown is not. Species with smooth face and crown may have erect scales on other parts of the head, particularly around the eyes and on the neck.

The forewing is essentially triangular, with the three sides being the costa (the leading edge), the termen and the dorsum (opposite the costa). The apex is the angle between costa and termen, the tornus is that between termen and dorsum. In narrow-winged species the termen and dorsum may merge into one, so there is no tornus. The terminal margin has a fringe of cilia (hair-like scales) which may extend along the dorsum. On the hindwings the cilia also extend along the dorsum.

The resting position of the moth is important. Several are illustrated in MBGBI 7 (2) covering a number of families. The front end or the rear end may be raised at an angle to the substrate. The wings may be arranged like the two sides of a pitched roof (tectiform), or rolled round the abdomen (involute), or they may be laid flat over the body, usually but not always partly overlapping. Sometimes they are extended, revealing the hindwings. The term involute covers a gradation from wings curving a little on the dorsal margin so that there is some overlapping near the base, to wings that are so inrolled as to give the moth a cylindrical appearance. Flat wings are folded so that one partly covers the other and the hindwings are completely covered. They are in fact rarely completely flat, but tend to be angled downwards. Extended wings are partly spread.usually in a horizontal plane, usually more or less exposing the hindwings.

The descriptions below are intended to aid the identification to family of adult moths. Characters and behaviour of the early stages are not included, although they very often give useful pointers to particular families.

After the descriptions of individual familes is a short appendix mentioning certain non-micros that are sometimes mistaken for microlepidoptera.

In the family accounts below, characters that are unique or nearly so to a particular family are written in bold type. Where a feature is the norm, it is not necessarily included in the description. Thus most moths have tongues, so lack of tongue is mentioned, but not presence unless it is a valuable distinction from otherwise closely related families.

There are undoubtedly omissions and inaccuracies in the text that follows. Any

errors should be reported to Martin Corley

MICROPTERIGIDAE (MBGBI Vol 1)

5 species. Diurnal. Often on flowers (Carex, Ranunculus etc). Wingspan 5-12 mm, resting with wings in tectiform position, forming steep angle. Forewings glossy bronze or purplish. Hindwings as broad as forewings. Head with spiky scales. Mandibles present but not easily seen. Maxillary palps (folded) and labial palps present, no tongue.

ERIOCRANIIDAE (MBGBI 1)

8 species. Diurnal, often flying over host trees. 9-14 mm wingspan, resting with wings in tectiform position. Forewings golden or purple. Hindwings as broad as forewings. Head with spiky scales. Mandibles absent, folded maxillary palps and labial palps present; tongue weak.

NEPTICULIDAE (MBGBI 1)

96 species. Wingspan 3-10 mm. Forewings resting in tectiform position, but at very shallow angle. Hindwings narrower than forewings, but with long dorsal cilia. Head with spiky scales. Antennae rather short, 1/3 to 2/3 length of forewing, with eye cap at base, usually contrasting in colour with head. Maxillary palps well developed. Labial palps reduced. Tongue absent

OPOSTEGIDAE (MBGBI 1)

4 species. Wingspan 7-12 mm. Very similar to Nepticulidae, usually larger, eye caps larger and same colour as head, which has flat scales apart from a tuft of erect scales between the antennae. Forewings white or pale, with or without markings.

TISCHERIIDAE (MBGBI 1)

5 species. Wingspan 6-11 mm. Rest with front end raised and wings in tectiform position. Forewings uniformly coloured or with a partial dark border. Hindwings narrower than forewings, with long dorsal cilia. Head with erect scales on top, flat scales on face. Antennae almost as long as wings, without conspicuous eye cap. Labial palps short, drooping. Maxillary palps rudimentary. Tongue short.

INCURVARIIDAE (MBGBI 1)

27 species. The family, as treated in MBGBI is now considered to consist of three families: INCURVARIIDAE, PRODOXIDAE and ADELIDAE. For convenience they are treated here as two families: Adelidae and Incurvariidae.

ADELIDAE 15 species. Wingspan 8-23 mm. Instantly recognisable by the very long antennae, much longer than the forewings (exception Adela fibulella, almost always found on Veronica chamaedrys flowers). Diurnal, with glossy wings except for Nematopogon. Many caddis flies have equally long antennae, but hold them pointing straight forwards, not spreading as in Adelidae.

INCURVARIIDAE 12 species. Wingspan 7-18m mm. Body held near horizontal at rest with wings in tectiform position. Forewings more than twice as long as wide (cf Psychidae), not glossy, brown or blackish, unmarked or with white or yellow spots on dorsal margin, or on dorsal and costal margins or with fasciae, one species with additional pale spotting. Hindwings as wide as forewings. Head with erect scales, or with smooth scales on face. Antennae shorter than forewing, simple or in the males of Incurvaria pectinate. Tongue reduced or absent.

HELIOZELIDAE (MBGBI 1)

5 species. Wingspan 5-9 mm. Adults fly by day in late spring over the host trees and shrubs. Wings held at rest in tectiform position at a steep angle. Forewings with pale dorsal spot or spots or with a fascia and a costal and a tornal spot. Hindwings slightly narrower than forewings, with long dorsal cilia. Head with smooth scales. Antennae 2/3 length of forewing. Labial palpi short, drooping. Tongue well developed.

PSYCHIDAE (MBGBI 2)

20 species. Females wingless except Narycia and Diplodoma. Three species without males. Wingspan 7-28 mm. Wings held in tectiform position. Forewings in many species not more than twice as long as wide, usually dull brown or grey, some species with speckled pattern, a few with indistinct fasciae. Hindwings as broad as forewings. Head with erect, raised or smooth scales. Mouthparts much reduced. Antennae bipectinate or in a few species with long cilia. The latter species may be confused with Tineidae.

TINEIDAE (MBGBI 2)

58 species. Wingspan 6-30 mm. Wings held in tectiform position. Forewings long, often without distict tornal angle, often dull brown. Hindwings as wide as forewings. Head with spiky scales (exception Psychoides with smooth scales). Labial palps pointing forwards or down, second segment with spreading bristles (sometimes difficult to see). Maxillary palps folded, tongue weakly developed. Antennae about ¾ length of forewings.

OCHSENHEIMERIIDAE (MBGBI 2)

3 species. Wingspan 9-12 mm. Diurnal. Forewings somewhat parallel-sided and with distict tornal angle. Hindwings as wide as forewings. Head densely covered with spiky scales. Labial palps covered with spreading scales. Antennae held at a wide angle, short, slightly over half length of forewing, often clothed with spreading scales.

Tongue present.

LYONETIIDAE (MBGBI 2)

21 species. Wingspan 5-10 mm. Resting position with front end raised (Leucoptera, Bedellia) or not (Lyonetia, Bucculatrix), wings in tectiform position. Forewings narrow. Hindwings narrow with long dorsal cilia. Head spiky scaled (Bucculatrix) or erect scaled on crown. Eye caps present, most conspicuous in Bucculatrix, absent in Bedellia. Antennae from 2/3 length of forewing to a little longer than forewing. Mouthparts all weakly developed. Modern treatments of the group divide them into three families: Lyonetiidae, Bucculatricidae and Bedelliidae. Bedellia could be mistaken for a Gracillariid.

HIEROXESTIDAE (MBGBI 2)

3 species. Only one species is found outdoors, and that only in the Scilly Isles. The others are imported with bananas. Wingspan 8-28 mm. Close to Tineidae, but face has a forward pointing keel of scales.

GRACILLARIIDAE (MBGBI 2)

90 species. Wingspan 4.5-16 mm. Rest with fore end raised at around 40º (except Phyllonorycter, only slightly raised), often showing tufts of scales on legs. Forewings at rest in involute position. Forewings narrow, without distinct tornus, markings absent or more often well developed. Hindwings narrow, with long dorsal cilia. Head smooth or erect scales. Antennae from nearly as long as to slightly longer than forewing, without eye cap. Labial palpus slender, pointing forwards. Tongue present.

PHYLLOCNISTIDAE (MBGBI 2)

3 species. Wingspan 6-8 mm. Closely related to Gracillariidae. Rest with body close to horizontal. Antennae 4/5 length of forewing with small eye cap. Wing markings resembling Leucoptera (Lyonetiidae) or Phyllonorycter (Gracillariidae).

CHOREUTIDAE (MBGBI 2)

6 species. Wingspan 9-18 mm. Diurnal. Rest with body horizontal, but held well up on legs and wings held flat and slightly diverging (except Tebenna with wings involute). Forewings broad. Hindwings broader than forewings. Head smooth scaled. Antennae half to 2/3 length of forewing. Labial palpi pointed forewards, with tufts of scales beneath second segment in some genera.. A very distinctive family. The broad wings suggest Tortricidae, but the resting position is quite different.

GLYPHIPTERIGIDAE (MBGBI 2 and 3)

8 species. 7 species of Glyphipterix were treated in MBGBI 2. The genus Orthotelia was added to the family in MBGBI 3. Wingspan 6-16 mm (Glyphipterix); 18-28 (Orthotelia). At rest the wings are raised and lowered in a characteristic fashion in Glyphipterix. Those of Orthotelia are kept motionless in a tectiform position. Forewings moderately elongate but with distinct tornus, hindwings broad, but not as broad as forewings. Head smooth. Antennae about 3/5 length of forewing. Labial palpus slender, slightly upcurved (strongly in Orthotelia). Tongue well developed (except Orthotelia). Most Glyphipterix species have a series of costal markings and a dorsal hook which could lead to confusion with Cydia spp. (Tortricidae). Orthotelia resembles one of the smaller `Wainscots’(Noctuidae). Orthotelia is very ill-matched with Glyphipterix. Its placement in this family is highly questionable.

DOUGLASIIDAE (MBGBI 2)

2 species. Wingspan 8-9 mm. Mainly diurnal. Rest with front end raised. Forewings narrow without tornus, dark grey, with or without spot or fascia.. Hindwings very narrow with long dorsal cilia. Head with smooth scales. Antennae without eye cap. Labial palps pointing foreward, short.. Associated with Vipers Bugloss (Echium).

HELIODINIDAE (MBGBI 2)

1 species, extinct in Britain since 1820.

YPONOMEUTIDAE (MBGBI 3)

76 species. Wingspan 7-33 mm. Wings at rest in tectiform or involute position, antennae rest along wings or pointing forwards, body held horizontal or with rear end raised. Forewings elongate, with or without distinct tornus. Hindwings as wide as forewings or sometimes and with long dorsal cilia. Head with smooth, raised or erect scales. Antennae about ¾ length of forewing, without eye cap. Labial palps pointing forwards or curved upwards, in Ypsolopha with long tuft of forward pointing scales on second segment. Tongue present, though sometimes weakly developed. A very diverse family, now sometimes split into several families or subfamilies. Yponomeutinae have rows of dots along the forewings. Ypsolophinae and Plutellinae have forward pointing antennae and tufted labial palps; some Ypsolopha have hooked wingtips. Acrolepiinae have upcurved labial palps and erect scales on crown.

ROESLERSTAMMIIDAE (MBGBI 3)