This glossary of entomology describes terms used in the formal study of insect species by entomologists.
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum (dorsal), the metasternum (ventral), and the metapleuron (lateral) on each side. The metathorax is the segment that bears the hindwings in most winged insects, though sometimes these may be reduced or modified, as in the flies (Diptera), in which they are reduced to form halteres, or flightless, as in beetles (Coleoptera), 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 of the Hymenoptera, the first abdominal segment is fused to the metathorax, and is then called the propodeum.
The propodeum, propodeon or propodium is the first abdominal segment in Apocrita Hymenoptera. It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is strongly constricted posteriorly to form the articulation of the petiole, and gives apocritans their distinctive shape. There may be a suture between the propodeum and the thorax, like in Symphyta or not, and the presence or absence of such suture can aid in identifying specimens.
The mesosoma is the middle part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the metasoma. It bears the legs, and, in the case of winged insects, the wings.
The metasoma is the posterior part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory system, and circulatory system, and the apical segments are typically modified to form genitalia. In a few of the most primitive insects, the metasomal segments bear small, articulated appendages called "styli", which are often considered to be vestigial. There are also pre-apical appendages in most insect orders, called cerci, which may be multi-segmented and almost resembling a posterior pair of antennae; these may be variously modified, or lost entirely. Otherwise, most adult insects lack appendages on the metasoma, though many larval insects have some form of appendages, such as prolegs or, in aquatic insects, gills.
The Leucospidae are a specialized group of wasps within the superfamily Chalcidoidea, that are ectoparasitoids of aculeate wasps or bees. They are typically mimics of bees or stinging wasps, often black with yellow, red, or white markings, sometimes metallic, with a robust mesosoma and very strong sculpturing. The hind femora are often greatly enlarged, with a row of teeth or serrations along the lower margin as in Chalcididae. The wing has a longitudinal fold. The female ovipositor is sometimes short, but if not, it is recurved and lies along the dorsal side of the metasoma, a unique feature. The males are also unusual, in the fusion of many of the metasomal segments to form a capsule-like "carapace".
Signiphoridae is a small family of parasitic wasps in the superfamily Chalcidoidea. The roughly 80 species are placed in four genera.
Sphecomyrma is an extinct genus of ants which existed in the Cretaceous approximately 79 to 92 million years ago. The first specimens were collected in 1966, found embedded in amber which had been exposed in the cliffs of Cliffwood, New Jersey, by Edmund Frey and his wife. In 1967, zoologists E. O. Wilson, Frank Carpenter and William L. Brown, Jr. published a paper describing and naming Sphecomyrma freyi. They described an ant with a mosaic of features—a mix of characteristics from modern ants and aculeate wasps. It possessed a metapleural gland, a feature unique to ants. Furthermore, it was wingless and had a petiole which was ant-like in form. The mandibles were short and wasp-like with only two teeth, the gaster was constricted, and the middle and hind legs had double tibial spurs. The antennae were, in form, midway between the wasps and ants, having a short first segment but a long flexible funiculus. Three additional species, S. canadensis, S. mesaki and S. nexa, were described in 1985, 2005, and 2024, respectively.
Insect morphology is the study and description of the 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 features separate insects from other arthropods: they have a body divided into three regions, three pairs of legs, and mouthparts located outside of the head capsule. This position of the mouthparts divides them from their closest relatives, the non-insect hexapods, which include Protura, Diplura, and Collembola.
Cebrionini is a tribe of click beetles from the family Elateridae; formerly ranked as a subfamily or family, they are now considered a tribe within the subfamily Elaterinae.
Kollasmosoma sentum is a parasitoid wasp in the family Braconidae, which lays its eggs inside adult ants. It was featured as one of "the top 10 new species of 2012" in a list compiled by Conservationists at the Arizona State University International Institute for Species Exploration.
Megaphragma is a genus of wasp in the family Trichogrammatidae. It contains some of the smallest known insects, Megaphragma caribea and Megaphragma mymaripenne, which are roughly the same size as some unicellular protozoans.
Zigrasimecia is an extinct genus of ants which existed in the Cretaceous period approximately 98 million years ago. The first specimens were collected from Burmese amber in Kachin State, 100 kilometres (62 mi) west of Myitkyina town in Myanmar. In 2013, palaeoentomologists Phillip Barden and David Grimaldi published a paper describing and naming Zigrasimecia tonsora. They described a dealate female with unusual features, notably the highly specialized mandibles. Other features include large ocelli, short scapes, 12 antennomeres, small eyes, and a clypeal margin that has a row of peg-like denticles. The genus Zigrasimecia was originally incertae sedis within Formicidae until a second species, Zigrasimecia ferox, was described in 2014, leading to its placement in the subfamily Sphecomyrminae. Later, it was considered to belong to the distinct subfamily Zigrasimeciinae.
Pristomyrmex tsujii is a species of ant in the genus Pristomyrmex. Known from Fiji, where they are widely distributed but rarely encountered. The species has a discrete ergatoid queen caste that is intermediate between a worker and an alate queen.
Quadrastichus erythrinae Kim, 2004, is a small parasitoid wasp belonging to the family Eulophidae, but also a secondary phytophage by way of inducing galls on the leaves, stems, petioles and young shoots of various Erythrina species.
Gerontoformica is an extinct genus of stem-group ants. The genus contains thirteen described species known from Late Cretaceous fossils found in Asia and Europe. The species were described between 2004 and 2016, with a number of the species formerly being placed into the junior synonym genus Sphecomyrmodes.
Aiura is a genus of parasitoid wasps belonging to the family Ichneumonidae and the subfamily Campopleginae.
Mesopeltita is a genus of chalcid wasps. The only species, Mesopeltita truncatipennis, is a parasitoid of coccid scale insects ; it has been found on pigeon pea, Cajanus cajan. The species has been found in many countries.
Platyscapa soraria is a species of fig wasp; it is the pollinator of Ficus ingens.
Calesidae is a small family of chalcid wasps, previously classified as subfamily Calesinae, in the family Aphelinidae. These tiny wasps are parasitoids of other small insects, mainly whitefly species, including the widespread pest Aleurothrixus floccosus.
