Glossary - Agricultural Entomology - page 283

Scutum The second of the main dorsal components
of each of the three sections of the thorax, usually
obvious only on the mesothorax (cf. Prescutum,
Scutellum); also, a roof-like shield over the
gnathosoma of a mite.
Segmental Pertaining to a segment or segments.
Sejugal furrow A suture or groove which divides the
idiosoma of a mite into the propodosoma and the
hysterosoma (q.v.).
Semiochemical A chemical used in interspecific or
intraspecific communication.
Serrate Toothed like a saw.
Seta (pi. setae) A small bristle.
Setose Covered with setae.
Shield A term of convenience for a large sclerotized
plate on the body of an insect or mite.
Siphunculus (pi. siphunculi) One of a pair of pores
or tube-like structures on the abdomen of an
aphid which discharge, for example, alarm
pheromones and other defensive secretions.
Spatulate Spade-like.
Spinneret A silk-producing structure containing silk
glands.
Spinose Spiny.
Spinule A small spine.
Spiracle A breathing pore - an opening of the tra-
cheal system.
Spiracular line A line on the body surface of a larva,
passing through the row of spiracles.
Squama (pi. squamae) A membranous flap at the
base of the wing of certain flies.
Stemma (pi. stemmata) In holometabolous insects,
the 'simple' eye (ocellus) of a larva, which is
sometimes capable of forming a relatively clear
image.
Sternal spatula A ventrally placed structure present
in third-instar larvae of most midges
(Cecidomyiidae), formed from the remains of the
head capsule and used to burrow into the soil
prior to pupation.
Sternite A ventral sclerite; also, one of the annulated
subdivisions on the ventral part of the hystero-
soma of an eriophyid mite.
Sternum The ventral surface of a segment.
Stigma (pi. stigmata) A distinctive, often reniform,
mark on the forewing of certain moths; also, in
certain mites, an external opening of the respira-
tory (tracheal) system (see also Pterostigma).
Striae Grooves running across or along the body
cuticle (such as those on the elytra of beetles).
Strigulae A series of short dash-like markings arising
from the costal margin of the forewings of certain
Lepidoptera (e.g. Tortricidae).
Style A slender bristle present at the apex of some
antennae.
Stylet A needle-like structure - often applied to
parts of the probing mouthparts of certain insects

and mites, and to parts of the sting of certain bees
and wasps.
Styliform Needle-like.
Stylophore The needle-like piercing mouthparts of a
mite, formed from the coalesced chelicerae.
Subdorsal Pertaining to or at the side of the dorsum.
Subspiracular line A line on the body surface of a
larva, passing just below the row of spiracles.
Suture A groove on the body surface which usually
divides one sclerite (plate) from another; also, the
division between the paired elytra of a beetle.
Tarsal formula In certain beetles, the specified
number of tarsal segments on the foreleg, mid-leg
and hindleg.
Tarsus (pi. tarsi) The distal part ('foot') of the leg of
an insect, usually subdivided into several seg-
ments; also, the fifth segment of the pedipalp of a
mite; also, the fifth (usually terminal) segment of
the leg of a mite.
Tegmen (pi. tegmina) The hardened, leathery
forewing of a cockroach, grasshopper, etc. (see
also Elytron).
Tegula (pi. tegulae) A small lobe covering the base
of the forewing.
Tergal Pertaining to the tergum.
Tergite A dorsal sclerite; also, one of the annulated
subdivisions on the dorsal part of the hystero-
soma of an eriophyid mite.
Tergum The dorsal surface of a body segment.
Thelytoky Parthenogenetic reproduction in which
only female offspring are produced.
Thorax The second of the three main divisions of
the body of an insect, bearing the legs and the
wings.
Thumb-claw In certain mites, a prehensile structure
on the pedipalps, formed from the tibial seta
(which forms the claw) and the palpal tarsus
(which forms the 'thumb').
Tibia (pi. tibiae) One of the segments of a leg, lo-
cated between the femur and the tarsus of an
insect or a mite; also, the penultimate segment of
the pedipalp of a mite, located between the genu
and the tarsus.
Triordinal Of three sizes.
Tritonymph The third nymphal stage of a mite.
Trochanter An often small and inconspicuous seg-
ment of the leg of an insect, located between the
coxa and the femur; also, the second segment of
the leg of a mite, located between the coxa and
the femur; also, the basal (first) segment of the
pedipalp of a mite.
True legs Thoracic legs.
Tubercle A small, rounded projection.
Tuberculate With tubercles (q.v.).
Tympanum The auditory membrane or 'ear' of an
insect.
Uniordinal Of one size.