Myrmeleon immaculatus

Adults are distinguished from damselflies by their short, clubbed antennae (damselflies have thread-like antennae). Within antlions, M. immaculatus can be recognized by its blue-grey coloration and moderate size (30 mm). The genus Myrmeleon is the only North American antlion genus whose larvae construct conical pits; other genera simply bury themselves just below the soil surface. Larvae are identified by their pit-building behavior and backward-only walking pattern.

Adults are found among tall grasses, particularly at dusk. Larval pits occur in fine, powdery soils or sawdust around rotten logs, typically in dry, sheltered locations such as beneath rock overhangs, under bridges, at the base of trees, or in the dirt floors of old barns and sheds. Colonies are rarely found in fully exposed situations.

Occurs in North America and Central America. Particularly common in the eastern United States. Recorded from Vermont and sand prairie habitats in Missouri.

Adults are most frequently observed at dusk. Activity in sand prairie habitats has been documented in early autumn (September).

Complete metamorphosis with four stages: egg, larva, pupa, and adult. Larvae dig conical pits in sandy soil and lie in wait beneath the bottom of the pit. Pupation occurs underground within a sand-incorporated silken cocoon. Adults are short-lived and do not feed extensively.

Larvae walk only backwards, rapidly, and dig pits by moving in reverse in a spiral pattern while throwing sand with their jaws and the flattened top of their head. When prey contacts the unstable pit walls, the larva senses vibrations and throws additional sand to accelerate the prey's descent. The larva then impales the victim with hollow mandibles, injects paralyzing enzymes that pre-digest tissues, and sucks out the liquified contents. The dry carcass is ejected from the pit with a violent head thrust. Larvae leave winding, spiraling trails in sand while searching for suitable trap locations—behavior that gives rise to the common name "doodlebug." Adults are weak, clumsy fliers and exhibit remarkable cryptic behavior: upon alighting on vegetation, they align their bodies so precisely with stems or twigs as to become essentially invisible.

Larvae function as sit-and-wait predators of small soil-dwelling arthropods, particularly ants. Their pit-trapping behavior represents a specialized foraging strategy that contributes to nutrient cycling in dry, sandy ecosystems.

Larvae are familiar to many people as "doodlebugs" and are sometimes kept in captivity for observation. They can be induced to throw sand or grasp objects by tickling them with grass blades or twigs. They have been used in educational contexts to demonstrate predator-prey interactions and trap-building behavior in insects.

• ScotoleonAnother antlion genus in North America; adults have much longer abdomens in males with more prominent bracket-like claspers. Larvae do not build pits, instead burying themselves just below the soil surface.
• GlenurusAntlion genus with spectacular black, white, and pink wingtips; much more visually distinctive than the blue-grey M. immaculatus.
• VellaGiant antlion genus with wingspan of 100-120 mm or more; adults frequently attracted to lights at night, unlike the more cryptic M. immaculatus.
• Damselflies (suborder Zygoptera)Superficially similar adult appearance with slender bodies and membranous wings, but distinguished by thread-like antennae versus the clubbed antennae of antlions.

• antlion
• doodlebug
• pit trap
• Neuroptera
• sand prairie
• sit-and-wait predator

• BugGuide
• Wikipedia
• GBIF taxonomy match
• NCBI Taxonomy
• Catalogue of Life
• Bug Eric: "Doodlebugs" (Antlions)
• A sand prairie autumn | Beetles In The Bush