Glossary - Agricultural Entomology - page 281

Metathorax The third of the three main sections of
the thorax of a insect.
Micropyle A small pore in the chorion of an insect
egg, through which sperm may enter.
Microtrichia Small, spine-like hairs.
Microtubercle A minute tubercle (q.v.).
Mid-legs The pair of legs arising from the
mesothorax.
Moniliform Bead-like.
Mouth-hooks That part of the cephalopharyngeal
skeleton (q.v.) formed from the mandibles.
Multiordinal Of several different sizes.
Multiserial circle Arranged in several concentric
circles.
Multivoltine Having several generations annually.
Nymph The immature growth stage of a
hemimetabolous insect, usually similar in general
appearance to the adult and often sharing similar
feeding habits.
Obtect pupa Appendages firmly fastened to the
body, as in Lepidoptera (cf. Exarate pupa).
Ocellar triangle A usually distinctly separate, trian-
gular part of the head of certain Diptera which
bears the ocelli.
Ocellus (pi. ocelli) A light-sensitive simple eye with
a lens but without an image-forming capability
(see also Stemma); also, a pigmented spot on the
wing of certain Lepidoptera.
Ommatidium (pi. ommatidia) One of the units
forming a compound eye.
Omnivorous Feeding on both animal and plant
material.
Ootheca (pi. oothecae) The purse-like, egg-contain-
ing case produced by cockroaches and other
Dictyoptera.
Operculum (pi. opercula) A lid-like structure.
Oral vibrissae The pair of long bristles arising from
just above the mouth of certain flies.
Ovipara (pi. oviparae) A female aphid that lays
eggs.
Oviparous Reproducing by laying eggs.
Ovipositor The egg-laying structure of an insect.
Ovisac A typically silken, cocoon-like sac containing
eggs.
Oviscapt An egg-laying tube formed from the termi-
nal segments of the abdomen.
Ovoviviparous Producing an egg which has a defi-
nite shell and hatches within the maternal body.
Paedogenesis Parthenogenetic reproduction in
which the adult stage is omitted (see Larval
paedogenesis; Pupal paedogenesis).
Paedogenetic larva A larva which gives rise to fur-
ther larvae by the process of paedogenesis (q.v.)
(see Larval paedogenesis).
Palp (pi. palpi, palps) A segmented, sometimes leg-
like, sensory structure arising from the maxilla or
the labium of an insect (see also Pedipalp).

Palpus (see Palp).
Papilla (pi. papillae) A small, often finger-like,
projection.
Parasite A species which lives in or on another (the
host), obtaining food from it but giving nothing in
return.
Parasitoid Typically, a parasite in which only the lar-
val stage is parasitic and the adult free-living - a
parasitoid usually kills its host.
Paratergal plates Small sclerotized plates on the
tergites, as in certain lice.
Parthenogenesis Reproduction which does not in-
volve fertilization.
Parthenogenetic Pertaining to parthenogenesis

(q.v.).
Patella (see Genu).
Pecten A comb-like tuft of hair, present on the base
of the antennae of some insects.
Pectinate Comb-like (cf. Bipectinate).
Pedicel The second segment of an antenna, between
the scape and the flagellum; also, in ants, an alter-
native name for the petiole (q.v.).
Pedipalp One of a pair of sensory, leg-like structures
arising from the gnathosoma of a mite.
Pedunculate Stalked.
Penellipse An incomplete (open) ellipse.
Petiolate Attached by a narrow stalk.
Petiole The narrow 'waist" found in certain
Hymenoptera.
Pheromone A semiochemical (q.v.) produced by an
organism and used to communicate with, and usu-
ally eliciting a predetermined response in, a re-
ceiving individual of the same species - alarm
pheromones and sex attractants are examples.
Phoresy The involuntary transportation of one or-
ganism by another, without involving parasitism.
Phoretic Pertaining to phoresy (q.v.).
Phytophagous Plant-eating, herbivorous.
Pilose Hairy.
Pinaculum (pi. pinacula) A small chitinized plate on
the body of a larva.
Pleuron (pi. pleura) A plate forming the side wall of
a thoracic segment.
Plumose With numerous feathery branches.
Polyembryony The embryo of a single egg subdivid-
ing to give rise, on hatching, to two or more larvae
(all of which will be of the same sex).
Polyphagous Feeding on a range of different kinds
of food or host plant, such as plants belonging to
more than one family.
Porrect Extended forward horizontally.
Posterior At or towards the rear.
Postscutellum A small, usually poorly developed
section of the mesonotum, located immediately
behind the scutellum - well developed in certain
flies.
Prepupa (pi. prepupae) The non-feeding develop-