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Caterpillars of Pacific Northwest
Forests and Woodlands

Glossary


adfrontal suture - a seam-like line on the frontal area of a caterpillar's head capsule.
allelochemical - a chemical derived from plants that may stimulate or deter feeding by caterpillars.
anal proleg - a proleg on the last segment of the abdomen.
anterior - to be in front; the area that is the forward-most section of a body part.
aposematic - a brightly colored organism that is typically poisonous.

biordinal - the tips of the crochets occur in a pattern of two rows.
biserial - the base of the crochets occur in a pattern of two rows.
bivoltine - two generations per year.

cardiac glycoside - an allelochemical found in certain plants, such as milkweed, and poisonous to most animals.
chalaza (pl. chalazae) - a single hair arising from an elevated base.
chrysalis - the pupa of a butterfly.
cleft - notched.
cocoon - the pupa of a moth wrapped in silk.
crochets - hooks present on the ends of the prolegs.
cryptic - an organism that blends into its surroundings.

diapause - a condition of arrested development.
diurnal - active during the day.
dorsal - the top or back area of the body.
dorsum - the upper side of the body.

eclose - to emerge from.

frass - insect feces.

gregarious - living in a group.

head capsule - the sclerotized (hardened) part of the head.
herbivorous - feeding on foliage.
holometabolous - an insect whose development involves a pupal stage.

inchworm - the caterpillar of geometrids which has only one pair of midabdominal prolegs.
instar - an immature insect between molts.

labium - the bottom-most part of the mouthparts upon which the caterpillar silk gland is located.
labrum - a flap-like part of the mouthparts just below the face used as a feeding guide.
larva - one of the immature stages in the life cycle of a holometabolous insect.
lateral - an area along the side of a body part.

mandible - a component of the mouthparts used for cutting and chewing food.
mesothorax - the second (middle) segment of the thorax from the head, abbreviated as T2.
metathorax - the third (last) segment of the thorax from the head, abbreviated as T3.
midabdominal proleg - prolegs on the middle abdominal segments.
middorsal - an area in the middle of the top region of a body part.
monophagous - feeding on only one kind of plant.
multiserial - the base of the crochets occur in a pattern of multiple rows.
multivoltine - more than two generations per year.

nocturnal - active during the night.

occiput - the top portion of the head capsule.
omnivorous - feeding on both plants and animals.
osmeterium - an eversible forked pouch in Papilionidae located middorsally on the prothorax.
oviposition - the laying of an egg.

parasitoid - a specialized insect predator whose young develop entirely on a single host and kill the host.
plusiine noctuids - a group of moths whose caterpillar typically has two pair of midabdominal prolegs.
polyphagous - feeding on many plant species.
posterior - to be behind; the area that is the back end of a body part.
predaceous - feeding on animals.
proleg - fleshy protuberance of the body wall creating a nonjointed leg.
prothoracic shield - a sclerotized plate on the first thoracic segment.
prothorax - the first segment of the thorax behind the head, abbreviated as T1.
pupa - the life stage of a holometabolous insect that follows the larval stage and within which metamorphosis occurs.

sclerotized - a hardened area of the skin.
scolus (pl. scoli) - a spine with multiple points.
semilooper - the caterpillar of plusiine noctuids.
setae - hairs.
silk gland - a silk-excreting gland in caterpillars on the underside of the labium.
spiracle - the opening of the respiratory system located along the lateral side of the body.
stemma (pl. stemmata) - the eyes on the head capsule, also called eyespots.
subdorsal - the body area part way between dorsal and lateral.
sublateral - the area below the lateral region of a body part.
subspiracular - the body area immediately below the spiracles.

triordinal - the tips of the crochets occur in a pattern of three rows.
triserial - the base of the crochets occur in a pattern of three rows.

uniordinal - the tips of the crochets occur in one row.
uniserial - the base of the crochets occur in one row.
univoltine - one generation per year.
urticating - stinging (hairs).

venter - the underside of the body.
ventral - the area on the underside of a body part.

warts - small bumps or short finger-like projections extending from the body wall.


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