Genus Ambeodontus Lacordaire

Ambeodontus tristis (Fabricius) (Figs. 8–12).

Egg. Ovoid, 1.8 mm long, yellowish, with smooth shell.

Mature Larva. Form cylindrical, tapering posteriorly. Length, 25 mm. Colour, white. Body setae slender, light coloured.

Head (Fig. 8) subcircular, widest at mid-length, slightly emarginate on the posterior dorsal margin. Occipital foramen widest behind mid-length. Mandible (Fig. 9) short, robust, basal portion transversely striate, narrowed toward apex, cutting edge gouge-like. Labrum oval, transverse, nearly twice as wide as long, anterior margin setose, setae on each side extending back to two-thirds, median area non-setose. Maxillary palpi (Fig. 10) 3-jointed, longer than femur plus tibia, 3rd joint longer than 2nd, process well developed on palpifer and 1st joint. Mala with setae on apex short, sparse and slender. Labial palpifer with three setae. Mentum with three setae on each side, submentum with one seta on each side. Maxillary sclerite with three or four setae. Epistoma not emarginate in middle. Anterior half of front with moderately dense short hairs. Frontal sutures indistinct. Lens of ocellus absent but dark pigment may show under the head capsule. Genal setae moderately dense, light coloured and slender. Hypostoma without setae.

Thorax. Pronotum (Fig. 11) not twice as wide as long, anterior two-thirds with moderately dense setae, posterior third striate with a few sparse setae posteriorly, notal spots pale yellow. Post-notal fold present. Mesonotum without X-shaped lines. Presternum and epipleurum fused, presternum setose, eusternum smoother with short setae and not distinct from presternum anteriorly. Legs 4-jointed, well developed. Peritreme of spiracle without pecten.

Abdomen with pleural tubercles present but pleural discs not evident. Ampules not prominent, alutaceous. Three anal lobes. Spiracles oval. Hind intestine with a sclerotized thickening (Fig. 12) of the intima.

Pupa. Form as in adult Head with two setae on each side between the antennal bases, three across the front, one on each side near base of labrum and three small setae on each side near apex of labrum. One seta on mandible, none on gena. Pronotum with four setae in a row across the anterior margin, none on the lateral margin. A group of setae on each side of the median line about mid-length, scattered setae posterior to these. Mesonotum with a group of about 20 setae posteriorly on each side of the median line. Abdomen with segments 1–6 with a single posterior row of pigmented setigerous spines, 7th with 6 or 7 recurved setigerous pigmented spines posteriorly on each side, 8th with 4 or 5 pigmented spines on each side at mid-length and about 4 pigmented setigerous spines on each side of the posterior margin. Femora with one or two pigmented spines near distal end. Elytra with sparse setae on apical half.

The adults are found from February to June. The eggs are laid in cracks or crevices of the wood or may be affixed to the surface, the larvae boring through the shell into the wood. This species is very destructive to structural timber in dwellings. In the native forest it breeds in dead podocarp timber, while in settled areas it is commonly found in the dead wood of Cupressus macrocarpa. The record of the European longhorn Hylotrupes bajulus L. from New Zealand is based on a misidentification of Gracilia minuta F. (Blair, 1937: 266). This species does damage similar to that of Ambeodontus, but the larvae may be separated by the presence in H. bajulus of three distinct ocelli on each side of the head.