Burrowing specializations in a lacewing larva (Neuroptera: Dilaridae)

Abstract Dilaridae are an ancient relict lineage of lacewings, whose life history is poorly known. We investigated the external morphology of the first and second instar larvae of Dilar duelli Aspock U. and Aspock H., 1995, based on reared and collected specimens by means of scanning electron microscopy. Larvae of Dilar are characterized by straight mandibulo-maxillary stylets, strengthened antennae and palps, absence of stemmata, robust prothoracic legs with asymmetrical pretarsal claws, greatly elongate and cylindrical abdomen, and large pygopods, all of these features appear to be adaptations to fossorial habits, allowing the larvae to move in the soil. Dilar undergoes drastic developmental changes between larval instars, changing from minute, stout first instars to long, slender third instars, characterized by an overly developed abdomen. Larvae of Dilaridae share several morphological and developmental features with Mantispidae and Berothidae, although phylogenetic evidence suggests that these traits arose independently in association with similar life habits.