Blue-Black Spider Wasps

Blue-black spider wasp resting on senna foliage
Scientific Name
Anoplius spp.
Pompilidae (spider wasps) in order Hymenoptera (ants, bees, wasps)

There are nearly 50 North American species of blue-black spider wasps (genus Anoplius). Like other spider wasps, they have long legs, with stout spines at the outer tip of the tibia segment of the hind legs. Many species in this genus are entirely black, with a bluish sheen, while many others have an orange marking on the abdomen.

Females hunt wolf spiders, grass spiders, and similar spiders on the ground, flicking their wings nervously. Like other spider wasps, they drag their spider prey into an underground burrow, then lay an egg on it. The wasp larva hatches and eats the paralyzed but still-living spider.

These wasps are often seen visiting flowers.

Learn more about this and other spider wasps on their group page.

Common Name Synonyms
Anoplius Spider Wasps
The blue-black spider wasps that have an orange patch on their abdomen apparently are the species that Mydas flies mimic. In this case of Batesian mimicry, the harmless fly looks intimidating to would-be predators because it looks almost identical to the spider wasps, which are capable of delivering a painful sting.
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About Land Invertebrates in Missouri
Invertebrates are animals without backbones, including earthworms, slugs, snails, and arthropods. Arthropods—invertebrates with “jointed legs” — are a group of invertebrates that includes crayfish, shrimp, millipedes, centipedes, mites, spiders, and insects. There may be as many as 10 million species of insects alive on earth today, and they probably constitute more than 90 percent all animal species.