Elachistidae was expanded by Hodges (1998), following the suggestion of Minet (1990), to include eight subfamilies: Stenomatinae, Ethmiinae, Depressariinae, Elachistinae, Agonoxeniinae, Hypertrophinae, Deuterogoniinae, and Aeolanthinae. Some of these families have previously been given family status or subfamily status within Oecophoridae and other families. Hodges defined Elachistidae by the apomorphic pupa with lateral condyles on abdominal segments 5-6 and 6-7, restricting their lateral movement as first mentioned by Minet (1990). In addition, the ventral surface of A9 often has two zones of recurved setae.
Hodges considered the Elachistidae to be a sister group to the remaining Gelechioidea. However, Kaila included Elachistidae as a derived clade within the oecophorid lineage of families, which he placed as a sister group to the gelechiid lineage of families (2004).
The family includes more than 165 genera and 3,270 species worldwide (Hodges, 1998). Larvae are leaf tiers, leaf rollers, leaf miners, seed feeders, stem borers, or external feeders on various dicots and monocots. The distribution and feeding habits are treated further in discussions of each subfamily.
Prior to being included within Elachistidae, this subfamily was included as a subfamily of Oecophoridae (Hodges, 1978) or as a separate family (Meyrick, 1906; Duckworth, 1964). Minet (1990) proposed inclusion of Stenomatinae in his expanded concept of Elachistidae. As defined by Hodges (1998), males have the second abdominal sternum lacking venulae and apodemes (homoplasious with Deoclonidae (Syringopainae). The abdominal terga of the adults lack spines. The genitalia are characterized by a valva bearing some thickened setae with bifid or multifid apices and an uncus that is uni-, bi-, trilobed, or absent. The hindwing is usually broader than the forewing, Rs is bent towards Sc near the end of the cell, and Rs and M1 are usually stalked (Scoble, 1992; Hodges, 1998). The male antenna is generally characterized by presence of long setae.
Stenomatinae include about 1,200 species of small to medium sized moths in more than 30 genera and are most diverse in the Neotropical Region, but also occur in Madagascar, India, New Guinea, Australia, and New Zealand. About 23 species in five genera, notably Antaeotricha, occur in America north of Mexico. Larvae feed as borers, leaf tiers, or leaf miners on living and wilted vegetation of a wide variety of plant families, although 35% of species with known hosts feed on Myrtaceae (Hodges, 1998). Pupation occurs within the larval shelter (Scoble, 1992).
Most Ethmiinae, at least those in North America, can be recognized superficially by their forewing shape and pattern: an elongate wing with longitudinal streaks or spots and a separation of fasciae and pigmented areas on the costal half of the wing from the lighter colored dorsal area. This subfamily has the forewing venation with R 5 terminating on the costa instead of the outer margin, an apomorphy shared with the sister taxa Depressariinae, Elachistinae, Agonoxeninae and some Hypertrophinae. The hindwing has Rs and M1 separate, a character shared with other gelechioids. Abdominal sternum II has only the venulae present, a homoplasious character shared with several other gelechioids. The gnathos is fused broadly with tegumen and has an apical projection that is spinose or is absent, and the phallobase is recurved (Hodges, 1998). Sattler (1967) distinguished Ethmiinae by the presence of an isolated costal lobe on male valva. The abdominal terga of the pupa are not spined (Scoble, 1992).
This subfamily includes more than 350 species in about 5 genera, and is most diverse in tropical-subtropical areas, especially those in seasonally arid areas (Hodges, 1998; Wei et al, 2007). The greatest diversity is in the northern Neotropical Region (Scoble, 1992). About 54 species in three genera, mainly Ethmia, occur in America north of Mexico. Larval hosts are mainly Boraginaceae and Hydrophyllaceae, although some species use Papaveraceae, Ranunculaceae, Rosaceae, Sabiaceae, and Scrophulariaceae (Hodges, 1998; Wei et al, 2007).
References: Common (1990), Keifer (1936), Minet (1990), Powell (1971, 1973, 1980, 1985), Sattler (1967), Stehr (1987), Scoble (1992), Wei et al. (2007).
Originally described as a family by Meyrick (1883), Depressariinae has been treated more recently as a subfamily of Oecophoridae (Gaede, 1939; Hodges, 1974, 1978; Scoble, 1992). Common (1990), Nielsen and Common (1991), and Minet (1990) raised this subfamily to family status. As defined by Hodges (1998), imagoes usually have a four-segmented maxillary palpus, hindwing with Rs and M1 separate, and fore- and hindwings broad. The abdominal terga usually lack spines, and the male genitalia are symmetrical with a gnathos composed of a single spinose lobe or sometimes two separate lobes (Scoble, 1992).
Depressariinae include about 600 species in about 80 genera and are most diverse worldwide, but absent from many island groups. Larvae feed as leaf tiers, seed feeders, and stem borers on dicots (17 families), including Apiceae, Asteraceae, Betulaceae, Corylaceae, Fabaceae, Fagaceae, Malvaceae, Rosaceae, Rutaceae, Salicaceae, Urticaceae (Hodges, 1998).
References: Common (1990), Gaede (1939), Hodges (1974, 1978, 1998), Kaila (2004), Minet (1990), Nielsen (1996), Nielsen and Common (1991), Scoble (1992).
Species are typically small sized and, consequently, are less collected than other members of the family. This subfamily is distinguished from other Gelechioidea by the following combination of characters: 1) hindwing lanceolate with Rs and M1 long stalked, 2) female retinaculum with anteriorly directed scales on CuA, 3) antennal pecten present (Hodges, 1998). Ocelli are generally absent, the antennal scape is large and often forms an "eye-cap." The forewings range from broad to narrow, but the hindwings are always narrow (Scoble, 1992).
The subfamily occurs worldwide and includes about 550 described species in 15 genera, primarily in the genus Elachista (Scoble, 1992; Hodges, 1998; Kaila, 1999).
Larvae are primarily leaf miners, but some are stem borers, on Poaceae (about 75%), but other species are miners of Boraginaceae, Commelinaceae, Cyperaceae, Juncaceae, Lamiaceae, and Loniceraceae (Hodges, 1998). Pupation usually occurs outside the mine in a cocoon or covering of silk, but the pupae of some species are exposed and attached by a girdle to the substratum (Scoble, 1992).
References: Braun (1948), Common (1990), Falkovitsch (1981), Hodges (1978), Kaila (1992, 1996, 1997, 1999a, 1999b, 2003, 2004), Kuroko (1982), Minet (1990), Powell (1980), Traugott-Olsen & Nielsen (1977), Wagner (1987).
Hodges (1978), Scoble (1992), and Koster and Sinev (2003) treated the Agonoxeninae as a family. Very few apomorphies are present, but these include the considerably enlarged valvellae (anellus lobes), the more or less weakened valvae, and the peculiar leg-shaped appendages of the pupa (Koster and Sinev, 2003). The latter character is a synapomorphy for Agonoxeninae and other subfamilies, including Ethmiinae and Hypertrophinae (Koster and Sinev, 2003). Hodges (1983), Scoble (1992), and others have included Blastodactini and Parametriotini as tribes (or subfamilies) of Agonoxenidae.
Larvae are usually twig- or bark-borers, miners, gall makers, or external feeders on various woody, rarely herbaceous, plants of various families, including Arecaceae, Euphorbiaceae, Proteaceae, Rosaceae, Theaceae, and Tiliaceae (Hodges, 1998; Koster and Sinev, 2003). Pupation occurs outside the larval habitat, but not in the ground (Hodges, 1998).
About 95 species in 23 genera are known to occur worldwide (Hodges, 1998). The family is especially well represented in tropical regions where many species were erroneously described in other groups of microlepidoptera.
References: Hodges (1978), Koster & Sinev (2003), Nielsen (1996), Scoble (1992).
Minet (1990) suggested that Hypertrophinae be included in his expanded concept of Elachistidae, but Nielsen (1996) subsequently gave this group family status. The genitalia are characterized by a valva bearing a free sclerite at the distal end of the sacculus, a supposed apomorphy but occurring also in Cryptophasa balteata (Xyloryctinae) (Hodges, 1998). The larva has the mesial crochets on A10 widely spaced or absent (Hodges, 1998).
Hypertrophinae include more than 50 species in 11 genera in Australia, Tasmania, and New Guinea. Larvae feed as external feeders within silk shelters on Myrtaceae, esp. Eucalyptus (Hodges, 1998).
References: Common (1980, 1990), Diakonoff (1954a), Hodges (1974, 1978, 1998), Minet (1990), Nielsen (1996).
Nielsen (1996) treated Deuterogoniinae as a subfamily in the Oecophoridae.
This subfamily of Elachistidae is defined by the tegumen being poorly developed and mesially membranous (unique within Gelechioidea), a weakly sclerotized uncus that is separated from the tegumen by a broad membrane, and a hindwing with an outer margin that is excavated below the apex (Hodges, 1998).
Immature stages, biology, and hosts are unknown, except for one record of an adult emerging from a cynipid gall on Quercus.
The subfamily includes four species in two genera, Deuterogonia and Paradeuterogonia in the Palearctic (eastern Europe, Japan, Taiwan) and Oriental (Thailand) Regions.
References: Fujisawa (1991), Hodges (1978), Saito (1987, 1989), Toll (1964).
The genitalia are characterized by the male having a valva broadly attached to the vinculum, usually parallel with the vinculum for basal 1⁄2, then directed posteriorly at a right angled lobe (an apomorphy within Gelechioidea) and an aedeagus ankylosed with the juxta (Hodges, 1998). The larva of one species feeds as a leaf roller on Cedrela (Meliaceae) (Fletcher, 1933).
The subfamily includes about 20 species in Aeolanthes in India and Western China (Hodges, 1998).
References: Clarke (1955b), Fletcher (1933), Hodges (1998).