Members of family Platygastridae are truly minute wasps, often black and shiny. Many in subfamily Scelioninae are red and black. Platygastrids are notable for having almost no visible wing venation. The family is named for another important trait: platygaster is from the Greek and means "flattened abdomen."
Persons armed with a microscope can separate platygastrids from similar wasps by counting the antennal segments. Platygastrid wasps have 9 or 10 antennomeres.
Platygastrids are parasitoids on the eggs or larvae of many different insect groups, each taxon specializing in one group. The hosts include spiders, white flies and mealybugs, assassin bugs, weevils, crickets, crabronid wasps, stick insects, and many other taxa (Masner and Hanson, in Hanson and Gauld 2006).
In North America about 200 species of Platygastrid wasps have been described; about half of these are in genus Platygaster (Arnett, 2000). The photos on this page are from North and South America America.
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