Momphidae
6 species in 1 genus are known from Block Island. All but one of the described Nearctic species in this family are placed in the type genus. Several Nearctic species, including all but one of the species known from Block Island, are specialized to feed on various tissues of primrose (<i>Oenothera spp.</i>)
Elachistidae
7 species in 3 genera are known from Block Island. Unusually among speciose taxa, the type genus of this family, which contains well over 100 Nearctic species, representing the great majority of the family’s Nearctic diversity, is far more diverse in boreal Canada and Alaska than farther south on the continent. Moths in this family are generally tiny to minute.
Cosmopterigidae
7 species in 6 genera are known from Block Island. This family of tiny to minute moths includes many species in the type genus with very narrow forewings with a patch of orange scales bordered by metallic scaling; many other species are shades of orange or dark gray to black. Many have patches of raised scales on the forewings.
Gelechiidae
61 species in 34 genera are known from Block Island. This family of mostly small to tiny moths is well represented in the Nearctic region and the most diverse pre-tortricid family on Block Island. About half of the three dozen or so unidentified species recorded on Block Island belong to this family.
Scythrididae
2 species in 1 genus are known from Block Island. Species in this family of small, often brown moths are generally day-flying and are frequently seen visiting asters. They can generally be recognized by their distinctive resting posture. This family is poorly represented in eastern North America.
Autostichidae
8 species in 5 genera are known from Block Island. This family is represented regionally mainly by small to tiny, dully colored moths.
Coleophoridae
17 species in 1 genus are known from Block Island. This family of tiny to minute and usually dull-colored moths is represented in the Nearctic region by hundreds of species, the majority of which are undescribed, in a single genus. The larvae construct protective and camouflaging cases taking a variety of forms, and they extend their bodies out from within their cases to either mine leaves through a small hole chewed through the epidermis or else feed on seeds.
Stathmopodidae
2 species are known from Block Island. This primarily Old World family is represented by just two described and likely one or more undescribed species in one genus within the Nearctic region.
Depressariidae
13 species in 7 genera are known from Block Island. The Nearctic representatives of this family of small to tiny moths come mainly in shades of brown or gray or in black and white.
Gracillariidae
36 species in 12 genera are known from Block Island. This family of tiny to minute moths includes mainly monophagous and oligophagous leafminers.