Glossary of Terms

The following terms are used in the online Field Guide to Rare Wisconsin Lepidoptera.*

Anterior

The portion of the insect body toward the head. Opposite the posterior portion.

Apex

The point of a wing that is between the costal margin and the outer margin; where the costal and outer margins converge.

Apical

The adjectival form of apex, which is the tip of a structure. The apical portion of a lepidopteran wing is the tip that is most anterior and farthest from the base (where the wing attaches to the body).

Basal

The basal portion of a lepidopteran wing is the region closest to the point of attachment to the body.

Cell

A portion of each wing that is relatively devoid of veins, although entirely surrounded by veins. The large cell located from the wing's base to near the center of the wing is called the discal cell.

Chevron

A shape of a mark, much like ">", found on some caterpillars and butterflies.

Chrysalis

A butterfly pupa.

Conspecific

Of the same species.

Costa

The most anterior (leading) edge of a wing. Also called costal margin.

Costal fold

The fold along the leading edge of the forewing of a butterfly. It often contains scent scales used to attract other butterflies.

Costal margin

The most anterior (leading) edge of a wing. Also called costa.

Diapause

An extended period in which an insect has very little metabolic activity and is thus relatively inactive.

Distal

Farther from the axis of the body; opposite of proximal.

Diurnal

Active mainly in the daytime.

Dorsal

The side of the insect that is opposite the side with the legs and mouth parts. The upper surface when the animal is sitting at rest, opposite the ventral surface.

Forewings

The most anterior pair of wings. The pair closest to the head.

Hindwings

The most posterior pair of wings.

Holarctic

Occurring in the temperate regions of the entire Northern Hemisphere.

Hostplant

The plant used for food by a specific species. Butterflies typically lay their eggs on the host plant used by the caterpillar. A single species of butterfly may use one or several species of plants as host plants.

Inner margin

The most posterior (trailing) edge of a wing.

Instar

An insect during a period within the larval phase of life, between two molts. For example, one could refer to a second instar caterpillar.

Larva (pl. Larvae)

A caterpillar; the second stage in the lepidopteran life cycle. The larva is a worm-shaped organism specialized for spectacular growth by means of nearly constant eating. The larva lacks two abilities that the adult will eventually have: flight and reproduction.

Lateral

On the side of a structure or body.

Lepidoptera

The name of the order of insects that includes the butterflies, skippers, and moths. The feature that distinguishes Lepidoptera from other insects is the possession of tiny overlapping scales on the wings of the adult. Other features of Lepidopteran adults include: four membranous wings, forewing and hindwing on each side of the body coupled at their base, and mouthparts (if present and functional) shaped into a sucking tube a proboscis). Features of larvae (caterpillars) include possession of chewing mandibles, stubby prolegs on the abdomen, and silk-producing glands.

Medial

The adjectival form of median, referring to the middle of the body or structure. If referring to the body, the medial line is equivalent to the midline. If referring to a wing, the middle of the wing.

Median

The middle part of the wing.

Outer margin

The edge of a wing that is farthest from the body; between the inner margin and the costal margin.

Oviposit

To lay eggs. The process of laying eggs is called oviposition.

Palp (pl. Palpi)

A feeding and sensory appendage on the larval head; also (through metamorphosis), the olfactory and cleaning appendage on the front of the adult head.

Patrol

A strategy of mate location used by male butterflies, consisting of constant flight.

Pectinate

Having narrow divisions like the teeth of a comb.

Polyphagous

Feeding on or utilizing many kinds of food.

Postbasal

The area of wing just beyond the base.

Posterior

The portion of the insect body toward the abdomen and genital opening. Opposite the anterior portion.

Postmedian

The area just past the middle of the wing and toward the wing margin.

Proximal

Closer to the axis of the body; opposite of distal.

Puddling

A behavior of some butterflies in which they congregate at puddles, moist soil, or dung to obtain moisture and salts.

Pupa (pl. Pupae)

The third stage in the lepidopteran life cycle. Although seemingly quiet as seen externally, the pupa is busily destroying most of its larval cells and replacing them by reproduction of relatively few cells that had no function in the larva. Thus, a nearly complete reconfiguration of the animal occurs beneath the pupal cuticle, to make the adult body.

Remnant-dependent

A term that describes a species that is generally restricted to the remaining high quality portions of certain natural communities (e.g. prairies or pine barrens). Today, many of these natural communities are fragmented and sparsely distributed vestiges (remnants) of areas that were once large and more contiguous.

Reniform

Kidney-shaped.

Scales

The defining anatomical structures of Order Lepidoptera. Scales are tiny modified bristles covering most of the body surface. Most scales of the wings are flattened and overlapping, resembling in miniature the shingles on the roof of a house. Scales contain the molecules (pigments) that provide much of the color of the lepidopteran wings. Some wing colors are produced by the interplay of light with microscopic structures of scales, rather than involving pigments.

Spiracles

Breathing holes located along the side of the body.

Stigma

A section of scent scales located on the forewing of a male butterfly (specifically Hairstreaks and Skippers) that produces pheromones, useful in attracting females.

Subdorsal

The area just below the top of the head.

Submarginal

That part of the wing which is between the median and postbasal area.

Submedian

The part of the wing just before its middle.

Subspecies

A taxonomic group that is a division of a species; usually arises as a consequence of geographical isolation within a species

Tail

A thin, relatively short extension of the rear of the hindwing. In some species, such as the Hairstreaks, it is thought to mimic insect antennae and thus mislead bird predators into biting at the wrong end and only getting a mouthful of wing while the butterfly escapes in the opposite direction.

Thorax

The middle portion of an insect's body (the others: head and abdomen). The thorax contains a portion of the digestive tract, and a rudimentary heart-like tube. It is the point of attachment for legs and wings.

Univoltine

Having one generation per year.

Ventral

The side of the insect that includes the legs and mouth parts. The underside of the animal when it is sitting at rest, opposite the dorsal side.

* Some definitions provided courtesy of The International Lepidopterists' Society.