Overview

There are three larval types, all of which feed on decaying plant material. The aquatic larvae of Byrrocryptus are elongate and subcylindrical, with long antennae, a mandible bearing 2 brushes of hairs at base, movable maxillae with the articulating area partly concealed behind the postmentum, which is expanded and longitudinally divided into 3 parts, paired gular sutures, laterally placed abdominal spiracles, T9 forming a sclerotised, concave plate, and segment 10 with a pair of lobes bearing several hooks and usually 2 osmoregulatory papillae. Ptilodactyla larvae, which occur in leaf litter and wet rotten wood, are more curved ventrally at apex, and have an articulated process at the mandibular base, an undivided postmentum, fused gular sutures, paired lateral defence glands on segment 8, no anal papillae and fewer anal hooks. The third larval type, which is also found in leaf litter, has simple mandibles, an undivided postmentum, very short antennae, the 8th spiracles placed at the end of a posteriorly projecting process, and S9 with a ventral operculum. [Lawrence 1987a, 1988b]

Description

Elongate, pubescent beetles with moderately long antennae, sometimes bearing narrow, articulated appendages attached to bases of segments 4--10. Head strongly deflexed; pronotum with sharp lateral carinae, which are almost always incomplete anteriorly, and strongly developed basal interlocking mechanism with crenulations; scutellum notched anteriorly; elytra often striate; tarsi simple, provided with ventral brushes, or sometimes with reduced 4th segment and membranous appendage on 3rd.

Distribution

The Australian fauna includes Byrrocryptus , with several species distributed along the East Coast and related species in New Zealand, Ptilodactyla , with a few species in North Qld, and an undescribed genus related to the Holarctic Paralichas . Adults are not common but may be collected at light.