The Riodinidae (or metalmarks) are a family of butterflies. The common name "metalmarks" refers to the small metallic-looking spots commonly found on their wings. There are approximately 1,000 species of metalmark butterflies in the world. Although mostly neotropical in distribution, the family is represented both in the Nearctic and the Old World. Distinguishing features Like the lycaenids, the males of this family have reduced forelegs while the females have full-sized, fully functional forelegs. The foreleg of males is often reduced and has a uniquely shaped first segment (the coxa) which extends beyond its joint with the second segment, rather than meeting it flush. They have a unique venation on the hindwing: the costa of the hind wing is thickened out to the humeral angle and the humeral vein is short.[1] Most species perch on the undersides of leaves with the wings held open and completely flat. [edit]Taxonomy and systematics Riodinidae is currently treated as a distinct family within the superfamily Papilionoidea, but in the past they were held to be the subfamily Riodininae of the Lycaenidae. Earlier, they were considered to be part of the now defunct family Erycinidae, whose species are divided between this family and the subfamily Libytheinae. Life cycle The eggs vary in shape but often appear round and flattened. The caterpillars are usually hairy, plump, and are the common overwintering stage. Pupae are hairy and attached with silk to either the host plant or to ground debris or leaf litter. There is no cocoon. Several genera of Riodi

idae have evolved intimate associations with ants, and their larvae are tended and defended by ant associates. This also is the case with several linages of Lycaenidae and contributed to arguments for the uniting the two families. It is now recognized that myrmecophily arose several times among Riodinidae and Lycaenidae clades. [edit]Foodplants The larvae feed on plants of the families Araceae, Asteraceae, Bromeliaceae, Bombacaceae, Cecropiaceae, Clusiaceae, Dilleniaceae, Euphorbiaceae, Fabaceae, Lecythidaceae, Loranthaceae, Malpighiaceae, Marantaceae, Melastomataceae, Myrtaceae, Orchidaceae, Rubiaceae, Sapindaceae, Zingiberaceae as well as bryophytes and lichens.The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: coxa (meaning hip, plural coxae), trochanter (compare trochanter), femur (plural femora), tibia (plural tibiae), tarsus (plural tarsi), ischium (plural ischia), metatarsus, carpus, dactylus (meaning finger), patella (plural patellae). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods[1] but modern arthropods have eight or fewer. It has been argued[2][3] that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a Hox-gene, could result in parallel gains of leg segments.