Maier, C.T.; Lemmon, C.R.; Fengler, J.M.; Schweitzer, D.F.; Reardon, R.C.; Caterpillars on the Foliage of Conifers in the Northeastern United States. Morgantown, WV. USDA Forest Service. Forest Health Technology Enterprise Team Connecticut Agricultural Experiment Station. FHTET-2004-01. March 2004. 151 p.
Abdomen: Last section of the body of a caterpillar that usually is composed of 10 visible segments (A1 to A10) and that follows the leg-bearing thoracic segments (see Figures 1 and 2).
Anal comb: Pronged fork generally located behind the anal plate and near the anus; comb-like structure used to eject frass.
Anal plate: Sometimes hardened area on the top of the last abdominal segment (A10), often distinctly colored in the caterpillars in the Tortricidae (see Figures 1 and 2).
Annulations: Shallow creases that ring especially the abdominal segments.
Antenna (plural: antennae): Elongate sensory structure located between the stemmata and clypeus or labrum near the bottom of the head of a caterpillar (see Figure 3).
Anterior: Toward the front or the head of a caterpillar.
Band: Transverse, colored strip that may encircle a segment of a caterpillar.
Chevron: Pattern having the shape of a "V" or an inverted "V".
Clypeus: Area or plate on the front of the head between the frons and the labrum (see Figure 3).
Conifer: Tree or shrub (Order Coniferales) that is mostly evergreen and bears cones (deciduous larches and non-cone bearing yews are exceptions).
Crochets: Hook-like claws on the ends of the abdominal prolegs that are used by the caterpillar to cling to leaves, bark, silk, and other substances (see Figures 1 and 2).
Cryptic: Similar to the background; camouflaged.
Cuticle: Skin or integument of a caterpillar.
Dorsal: On the top or back of a caterpillar; above.
Dorsal glands: In the Lymantriidae, eversible, probably defensive, organs usually in the center of the dorsum of A6, A7, or both of a caterpillar; in the Lycaenidae, organs on A7 that produce sugary secretions to attract ants who, in return, protect the caterpillar.
Dorsum: Upper side or back of a caterpillar.
Family: Category in animal or plant classification that is above the genus and tribe and below the order; group of genera that share similar characteristics. (Scientific family names of insects always end in -idae).
Frass: Pellet-like excrement of a caterpillar.
Frons (or frontal triangle): Triangular plate on the front of the head that lies above the clypeus (see Figure 3).
Hard pines: Species of pines (such as jack, pitch, and red pines) that have hard wood and have needles in bundles of two or three.
Head: Fused anterior segments that bear the mandibles, antennae, eyes, and other sensory structures (see Figures 1-3).
Herringbone: Pattern made up of rows of parallel lines in which any two adjacent rows slope in opposite directions.
Holarctic: Biogeographical region including the northern parts of the New and the Old World; the Nearctic and the Palearctic regions combined.
Horn: Rigid and pointed cuticular outgrowth, especially on the thorax or abdomen of caterpillars in the Saturniidae and the Sphingidae.
Instar: Caterpillar between two successive molts. Typically the instars are numbered in sequence from the first to the last.
Labrum: Upper lip attached dorsally to the clypeus; structure used to help a caterpillar position foliage for eating (see Figure 3).
Lappets: Body lobes or outgrowths usually in the subspiracular or subventral region. Larva (plural: larvae): Caterpillar stage; in Lepidoptera, the feeding stage between the egg and the pupa.
Larva: (plural: larvae): Caterpillar stage; in Lepidoptera, the feeding stage between the egg and the pupa.
Lateral: On or toward the side of a caterpillar; used by some to describe the position of a longitudinal stripe of a caterpillar.
Line: Narrow, elongated mark that usually extends discontinuously or continuously for one to a few segments; a very narrow longitudinal mark that touches or runs near a wider longitudinal stripe.
Lobe: Typically rounded area that is above the eyes on each side of the head of a caterpillar (see Figure 3).
Looper: Caterpillar in the Geometridae or the Noctuidae with some of its prolegs reduced or absent, requiring it to move by looping its body forward.
Mandibles: Tooth-like jaws of caterpillars that are used to tear and chew foliage and other food material (see Figure 3). Mature caterpillar: Caterpillar of the final instar; the instar that precedes pupation.
Mature caterpillar: Caterpillar of the final instar; the instar that precedes pupation.
Middorsal: Along the middle of the back; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figure 4).
Mine: Chamber, usually inside a needle or between the upper and lower leaf surfaces, that is created by the feeding of a caterpillar and that often is occupied by it; when a caterpillar eats tissue from the inner needle or leaf while reaching below the surface or while occupying a hollow where the tissue has already been consumed.
Molt: To shed the old skin or cuticle to reveal the new, larger one below.
Oblique: Not perpendicular or parallel to the body axis; usually used to describe a slanted, lateral mark on abdominal segments, such as in many caterpillars in the Sphingidae.
Order: Category in animal and plant classification that is above the family and below the class; group of families that share similar characteristics. (Scientific names of insect orders end in -a).
Posterior: Toward the rear of a caterpillar; behind or rear.
Prolegs: Single pairs of false legs on the bottom of two to five abdominal segments, typically on A3 to A6 and A10 (see Figures 1 and 2).
Prothoracic shield: Dorsal portion or plate of the first thoracic segment (T1), often distinctly colored in caterpillars in the Tortricidae (see Figures 1 and 2).
Pupa (plural: pupae): Usually inactive developmental stage between the caterpillar and the adult (known as the chrysalis in butterflies).
Reticulation: Network of fine lines.
Sclerotized: Hardened; not fleshy or soft.
Spiracle: Lateral opening to the respiratory system; one pair on T1 and on A1 to A8 (see Figures 1 and 2).
Spiracular: Pertaining to or near the spiracle; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figure 5).
Stemma (plural: stemmata): Simple eye of a caterpillar, usually arranged in a group of six on each side of the head (see Figure 3).
Stripe: Broad line or streak that usually extends continuously or discontinuously for the length of the thorax and abdomen (and sometimes head) of a caterpillar.
Subdorsal: About midway between the middorsal and supraspiracular regions; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figures 4 and 5).
Subspiracular: Just below the level of the spiracles; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figure 5).
Subventral: Between the subspiracular and ventral regions; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figure 5).
Supraspiracular: Just above the spiracles, or between the subdorsal and spiracular regions; usually used to describe the position of a longitudinal stripe of a caterpillar (see Figure 5).
Thorax: Body region between the head and abdomen that is composed of three segments (T1 to T3) that bear the pairs of true legs (see Figures 1 and 2).
Transverse: Across a segment, or perpendicular to the long axis of the body of a caterpillar.
Tubercle: Distinct swelling of the integument that is variable in form, sometimes being low and broad or long and narrow.
Venter: Bottom or underside of a caterpillar.
Ventral: Below or underneath a reference point; underneath.
