What is "microstigmus"

The thin-waisted social wasps (genus Microstigmus), which typically resides in neotropic regions from Central to South America, are a small genus of wasps that build nests and live in colonies ranging in size from 1 to 18 members. Microstigmus is widely considered to be the only true eusocial species within the Crabronidae family. Like all Hymenoptera, Microstigmus has an interesting sex determination pattern. Females are 2n ( diploid), spawning from eggs that have been fertilized, while males are 1n ( haploid) and spawn from unfertilized eggs. Female wasps contain the eggs within their egg sac and have the option of fertilizing them or not, thus having complete control on the gender of the offspring. This wasp genus, part of the suborder Apocrita, is distinguished physically by the narrow waist (petiole) between the end segment of the thorax ( mesosoma) and the beginning of the abdomen ( metasoma). Specifically, it is in the subgroup of " apoid wasps", those that exhibit social behavior in nesting and foraging. Evidence does exist that in some species social altruism is visible; however, studies on these topics have been limited. The small size and enclosed nest structure makes it difficult to obtain significant data. Although it was originally classified under the Sphecidae family due to its elongated petiole, Microstigmus has been reclassified into the new Crabronidae family.