The metathorax is the posterior of the three segments in the
thorax
The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen.
In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...
of an
insect
Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
, and bears the third pair of
legs. Its principal
sclerite
A sclerite (Greek language, Greek , ', meaning "hardness, hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instea ...
s (
exoskeletal plates) are the metanotum (
dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
The fus ...
), the metasternum (
ventral
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
), and the metapleuron (
lateral
Lateral is a geometric term of location which may also refer to:
Biology and healthcare
* Lateral (anatomy), a term of location meaning "towards the side"
* Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx
* Lateral release ( ...
) on each side. The metathorax is the segment that bears the
hindwings
Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwi ...
in most winged insects, though sometimes these may be reduced or modified, as in the flies (
Diptera
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...
), in which they are reduced to form
halteres
''Halteres'' (; singular ''halter'' or ''haltere'') (from , hand-held weights to give an impetus in leaping) are a pair of small club-shaped organs on the body of two Order (biology), orders of flying insects that provide information about ...
, or flightless, as in beetles (
Coleoptera
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
), in which they may be completely absent even though forewings are still present. All adult insects possess legs on the metathorax. In most groups of insects, the metanotum is reduced relative to the
mesonotum. In the suborder
Apocrita
Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" ( petiole) formed ...
of the
Hymenoptera
Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic.
Females typi ...
, the first abdominal segment is fused to the metathorax, and is then called the
propodeum
Propodeum labelled within the alitrunk of an ant worker
The propodeum is a term that can refer to unrelated structures in insects or in mollusks.
Insects
The first abdominal segment in Apocrita Hymenoptera (wasps, bees and ants) is known a ...
.
See also
*
Glossary of entomology terms
This glossary of entomology describes terms used in the formal study of insect species by entomology, entomologists.
A–C
A synthetic chlorinated hydrocarbon insecticide, toxic to vertebr ...
*
Insect morphology
Insect morphology is the study and description of the morphology (biology), physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical f ...
*
Mesothorax
The mesothorax is the middle of the three segments of the thorax of hexapods, and bears the second pair of legs. Its principal sclerites (exoskeletal plates) are the mesonotum (dorsal), the mesosternum ( ventral), and the mesopleuron (lateral) ...
*
Prothorax
The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum ( ventral), and the propleuron (lateral) on ...
*
Thorax (insect anatomy)
The thorax is the midsection ( tagma) of the hexapod body (insects and entognathans). It holds the head, legs, wings and abdomen. It is also called mesosoma or cephalothorax in other arthropods.
It is formed by the prothorax, mesothorax and me ...
References
Insect anatomy
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