Alcaeus Dallas, 1851

Photo © Matthew Bulbert, Australian Museum

Type species:

Atelocerus varicornis Westwood, 1837 by original designation.

Number of Australian species:

Four.

Extralimital Distribution:

No.

Australian Distribution:

Temperate, tropical, subtropical regions; New South Wales, Queensland, Northern Territory, South Australia, Australian Capital Territory, Victoria and Western Australia.

Biology:

Unknown.

Host(s):

Alcaeus hermannsburgi Distant, W.L., 1910 associated with Acacia sp. [MIMOSACEAE], Cassia artemisioides Gaudich. [CAESALPINIACEAE], Cassis sp. [CAESALPINIACEAE].

Alcaeus lignicolor Walker, F., 1867 associated with Callitris preissi Miq. [CUPRESSACEAE] Native Pine, Melaleuca sp. [MYRTACEAE].

Alcaeus varicornis Westwood, 1837 associated with Acacia longifolia (Labill.) F. Muell. [MIMOSACEAE], Acacia stenophylla Cunn. ex Benth [MIMOSACEAE], Exocarpus aphyllus R.Br. [SANTALACEAE] Leafless Ballart.

Diagnosis:

Colour

Dorsally and ventrally mottled pale and dark brown, legs and antennae mottled pale and dark brown.

Texture

Dorsally and ventrally densely and uniformly punctate.

Vestiture

Dorsally glabrous. Ventrally covered with long, fine hairs. Antennae covered in very short, fine hairs; legs with long, fine hairs on femora and tibia.

Structure

Body - Elongate-ovoid, dorsally convex. Length 6.0 mm - 15.0 mm; width 5.5 mm - 10.5 mm.

Head - Subtriangular, moderately dorsoventrally orientated, as long as pronotum; jugae as long as or longer than clypeus, joined (meeting apically), expanded into spine-like process apically, laterally carinate; antennifer processes absent; antennae four segmented, appearing to be five segmented, first antennal segment longer than distance between eyes, inserted into head below mid-height but above ventral margin of eyes; bucculae elongate (posteriorly beyond antennifers); vertex cross-sectional shape convex; labium reaching between middle and hind coxae, first labial segment about as long as bucculae; eyes not stylate, directed laterally.

Pronotum - Calli present and well developed; anterior lobe surface excavate; humeral angles angulate and slightly expanded laterally; lateral margins explanate; anterolateral margins crenulate and concave; posterolateral margins sinuate; posterior margin straight to slightly sinuate.

Scutellum - Triangular, apex narrowly rounded and reflexed (tip pointing upwards); Y-shaped raised area present; lateral calli present as deep, dark pits; medial callus absent.

Thoracic sterna - Prosternum sulcate, without margin processes; mesosternum with low raised keel; metasternum not sulcate.

External efferent system - Evaporative scent gland covering about half metepisternum; peritreme elongate, apically pointed.

Hemelytra - Macropterous, about as long or slightly longer than abdomen; membrane veins reticulate.

Legs - fore tibia sulcate.

Abdomen - Connexiva visible dorsally; lower laterotergites armed with very small posterolaterally directed spines.

    
Copyright © Australian Museum 2002
Authors: Gerry Cassis, Emma Betts and Michael Elliott