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 between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host or in a nest cell provisioned by their mothers.
The superfamily Ichneumonoidea contains one extinct and three extant families, including the two largest families within Hymenoptera: Ichneumonidae and Braconidae. The group is thought to contain as many as 100,000 species, many of which have not yet been described. Like other parasitoid wasps, they were long placed in the "Parasitica", variously considered as an infraorder or an unranked clade, now known to be paraphyletic.
The Sphecidae are a cosmopolitan family of wasps of the suborder Apocrita that includes sand wasps, mud daubers, and other thread-waisted wasps.
The Crabronidae are a large paraphyletic group of wasps, including nearly all of the species formerly comprising the now-defunct superfamily Sphecoidea. It collectively includes well over 200 genera, containing well over 9000 species. Crabronids were originally a part of the Sphecidae, but the latter name is now restricted to a separate family based on what was once the subfamily Sphecinae. Several of the subfamilies of the Crabronidae are often treated as families in their own right, as is true of the most recent phylogenies.
Gall wasps, also traditionally calledgallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generally very small creature are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America.
The Spheciformes is a paraphyletic assemblage of insect families which collectively comprise the "sphecoid wasps". Larvae are carnivorous.
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.
Aculeata is a subclade of Hymenoptera containing ants, bees, and stinging wasps. The name is a reference to the defining feature of the group, which is the modification of the ovipositor into a stinger. However, many members of the group cannot sting, either retaining the ovipositor, or having lost it altogether. A large part of the clade is parasitic.
Proctotrupoidea is a hymenopteran superfamily containing seven extant families, though others have been recognized in the past, most of these having been removed to a recently erected superfamily Diaprioidea. Of the remaining families, only Proctotrupidae contains a substantial number of species, with over 400 described. The others are small, often relictual groups. See links for individual families for details of life history and diversity.
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".
Heterogynaidae is a minor and disputed lineage of small spheciform wasps occurring in Madagascar, Botswana, Turkmenistan, Oman, the United Arab Emirates, and the Eastern Mediterranean area. The majority are dark in color and range in size from approximately 1.5 to 5.0 mm. Most specimens have been collected in arid climates, but one species from Madagascar is known to occur in a humid forest habitat. Although males have functional wings, heterogynaid females are typically brachypterous, a trait which is unique among spheciform wasps. Wing venation is reduced in both sexes. All species are diurnal, with the exception of H. nocticola. Other aspects of their biology are completely unknown, but details of their morphology have prompted researchers to hypothesize that they may be non-fossorial parasitoids adapted to hunt in tight spaces, such as under tree bark. This is speculative and has not yet been confirmed by actual observations of behavior. It is also possible that modifications of the female metasomal tergum VI and gonostyli may represent a unique prey transport mechanism, but this is also unconfirmed.
Mellinidae is a small family of wasps, comprising 17 described species in two genera. This group has traditionally been treated as a subfamily within Crabronidae (Mellininae), but recent phylogenomic studies have shown it to be a distinct family.
Bothynostethini is a small neotropical tribe of solitary wasps partly recognizable for having peculiar modifications at the apex of the hind femora.
The subfamily Pemphredoninae also known as the aphid wasps, is a large group in the wasp family Crabronidae, with over 1000 species. Historically, this subfamily has frequently been accorded family status. In some recent phylogenetic analyses, one of the subtribes within this group is the sister lineage to the superfamily Apoidea, and accorded family rank as Ammoplanidae along with Pemphredonidae and Psenidae so as to keep families monophyletic.
Psenulus is a genus of wasps in the family Crabronidae. The 160 species are found worldwide, but are best represented in the Indomalayan realm with 68. The Palearctic has 26, the Nearctic 4, and the Australasian realm 3. Psenulus is largely absent from South America and entirely absent from Melanesia and Polynesia. A recent phylogenetic analysis provided strong evidence that this genus is the closest living relative to bees.
Diaprioidea is a hymenopteran superfamily containing five extant families, though in the past these families were included in the superfamily Proctotrupoidea.
Psenini is a tribe of aphid wasps in the family Crabronidae. There are about 11 genera and at least 460 described species in Psenini.
Miscophus is a genus of square-headed wasps in the family Crabronidae. There are more than 180 described species in Miscophus.
Ammoplanidae is a family of aphid wasps formerly treated as the Crabronidae subtribe Ammoplanina. There are about 10 genera and at least 130 described species in Ammoplanina. Phylogenetic analyses in 2018 and 2021 have confirmed this group as the sister lineage to the bees, and thus accorded the group family rank.
Condylognatha or Panhemiptera is a monophyletic grouping (superorder) that contains Hemiptera and Thysanoptera (thrips). Condylognatha belongs to Paraneoptera, which include its sister group, lice (Psocodea).
