Scutellum
Encyclopedia
The scutellum is the posterior portion of either the mesonotum or the metanotum of an insect
thorax
; however, it is used almost exclusively in the former context, as the metanotum is rather reduced in most insect groups. In the Hemiptera
, and some Coleoptera, the scutellum is a small triangular plate behind the pronotum
and between the forewing bases. In Diptera
and Hymenoptera
the scutellum is nearly always distinct, but much smaller than (and immediately posterior to) the mesoscutum
.
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
thorax
Thorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
; however, it is used almost exclusively in the former context, as the metanotum is rather reduced in most insect groups. In the Hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
, and some Coleoptera, the scutellum is a small triangular plate behind the pronotum
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 are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
and between the forewing bases. In Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
and Hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...
the scutellum is nearly always distinct, but much smaller than (and immediately posterior to) the mesoscutum
Mesothorax
The mesothorax is the middle of the three segments in the thorax of an insect, and bears the second pair of legs. Its principal sclerites are the mesonotum , the mesosternum , and the mesopleuron on each side...
.