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Genus Ochrocydus Pascoe
Ochrocydus huttoni Pascoe (Fig. 27).
Egg. (Ovarian) fusiform, length 5 mm.
Mature Larva. Form stout, cylindrical, length up to 60 mm. Colour creamy yellow. Body covered with short castaneous setae and sparse longer and stouter hairs.
Head (Fig. 27) sub-quadrate, sides sub-parallel, slightly wider behind mid-length. Occipital foramen with sides sub-parallel, widest anteriorly. Mandible normal. Labrum slightly wider than long. Maxillary palp longer than femur plus tibia, processes on palpifer and basal joint of palp, last joint about half as long as 2nd and slightly shorter than last joint of labial palp. Labial palp with joints subequal. Epistoma slightly emarginate. Antennae partially retractile, first and second joints subequal, 3rd half length of 2nd. Three ocelli. Genal setae sparse and stout. Hypostoma with two or three setae on each side.
Thorax. Pronotum transverse but not twice as wide as long, beset with dense stout setae across anterior margin and sparser setae behind the notal spots, which are prominent and castaneous. Notal plate white posteriorly. Two or three setae in posterior angles of pronotum. Post-notal fold present. Metanotum with X-shaped suture. Presternum fused with epipleurum and with eusternum. Legs well developed, 4-jointed.
Abdomen with neither pleural tubercles nor discs evident. Ampullae broad, sub-tuberculate, contrasting with the integument owing to the minute and dense pigmented spinules with which they are beset. Spiracles large, oval. Three anal lobes. Hind-intestine without sclerotized thickening of intima.
Pupa. Form as in adult. Head with a few poorly developed setae, six small setae on front, two on clypeus, one on mandible and none on gena. Pronotum with a median group of setae anteriorly and scattered setae on disc. Mesonotum with sparse small setae. Metanotum with
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sparse small setae posteriorly. First abdominal segment with a posterior row of setigerous spines and three or four on each side of median line anteriorly. Segments 2–6 with a more or less complete oval ring of setigerous spines formed by the joining of the anterior and posterior rows, and a group of three or four setae on each side at mid-length. Seventh with a number of setigerous spines forming a rough ring. Eighth with five or six setigerous spines. Femora, tibiae, and elytra without setae. Trochanters without processes.
Larvae and pupae were taken from Nothofagus solandri at Wakefield in September. This species causes extensive damage to the timber of living beech trees by boring between the bark and the wood and constructing tunnels over half an inch in diameter in the wood. When ready to pupate the larva constructs a vertical pupal chamber which is about 5 inches in length and opens by a horizontal passage to the outside. The pupal chamber is blocked at both ends by very coarse shreds of wood. Infested trees show the exit holes and often an accumulation of sawdust-like frass at the base of the tree. Isolated trees, such as those left after bush felling, are commonly attacked.