Apotrechus unicolor
Workbook
Genus Apotrechus
(from Rentz and John 1990 Invertebrate Taxonomy 3: 1053)
Apotrechus illawarra
distinguished from all other gryllacridids by the following combination of characters: size moderate to very large: species apterous; frons reddish brown below antennal socket or with an oblique brown stripe on genae;
middle tibia with a dorsal apical spine on posterior margin; hind femur with a few teeth on both margins of ventral surface near apex, these preceded by a densely packed row of setae along entire margin; ovipositor very short, barely protruding beyond tip of abdomen. colour very light or pale; abdomen without banding.
Size moderate to large, often megacephalic, form very robust. Both sexes apterous. Head with fastigium of vertex very low, margins not carinate. Head very large, frontally flattened, without carinae, but with minute rugulae. Mandible (Figs 253, 254) elongate, teeth positioned along entire length of internal margin; outer margin undulating, with a deep sulcus at base; incisor stout, dentes tubercle-like, bases not raised; molar area short, low; setal row of external surface short, setae elongate, internal surface with an arched row of short setae. Maxilla (Figs 259, 260) with galea (Fig. 260) short, broad, straight, without longitudinal carina; base with 4 widely spaced tubercles; adjacent base of lacinia with 4 tubercles, the basal 3 closely packed, the apical tubercle much larger, positioned adjacent to apical tubercle on ga1ea;-lacinia (Fig. 259) broad at base, strongly arching, apex with teeth low, closely spaced. Scape elongate, about as long as eye, with a weak swelling on internal margin at base; pedicel and first segment of flagellum as long as scape. Median ocellus absent; lateral ocelli absent or faintly indicated. Pronotum not specialised, surface generally flat, cephalic margin truncate to weakly undulating, caudal margin weakly concave; 3 low callouses present on each side laterally; lateral lobe shallow, ventral margin truncate to weakly undulating. Meso- and metanota flat but ~ i t h 1-2 depressions on each side proximally. Fore coxa armed with a short, knob-like tooth or a minute spine. Fore and middle femora unarmed; fore femur about as long as pronotum; hind femur short, robust, considerably swollen basally, armed ventrally near apex on outer margin with 1-4 teeth, internal margin with a smaller number of teeth; stridulatory ridge (Fig. 3 11). Fore tibia with 5 spines on both margins on ventral surface, these positioned along apical four-fifths of tibia; middle tibia with 4 or 5 spines on each margin of ventral surface, depending upon the species, dorsal surface with an apical spine on posterior margin. Hind tibia subcylindrical, dorsal surface flattening near apex and slightly arched subapically; dorsal surface unarmed except for 2 minute apical spurs, ventral surface with 4 similar spurs preceded by 2 subapical elongate spines. Spines sparsely setaceous, spurs and teeth smooth. Abdominal stridulatory area (Fig. 310) with 2 oblique rows of pegs on tergite 11, the more anterior of which is shorter and at a more oblique angle, tergite 111 with 2 widely separated parallel rows. Male tergite IX bulbate, apex weakly divided; intercercal teeth large, divergent; cerci large, erect, divergent.
Subgenital plate broad, without styles, with a short median projection and with or without tubercles laterally; apex divided, distinctive of species. Female cerci elongate, arching upward; subgenital plate very short, broad, with an apical rim surrounding a soft median portion. Ovipositor minute, scarcely projecting beyond tip of abdomen, rigid, highly sclerotised.
General overall colour very pale creamish or whitish yellow, often with a greenish overcast. Frons castaneous below antenna1 socket. a whitish vellow with an oblique stripe on gena. Clypeus white, with a faint brown spot on either side: labrum yellow brown. Eye black, dorsal internal margin white. Antenna1 scape, pedicel and first segment of flagellum light yellow brown, flagellum contrastingly darker. Occiput with or without an irregular pattern. Pro-, meso- and metazona each with a pattern of light spots seemingly indicating muscle attachment. Abdomen light creamish yellow, without indication of bands. Ovipositor medium brown.
Apotrechus species live in leaf litter in the forest understorey where they bind dry leaves, twigs and debris together to form a shelter (Figs 84, 85) in which they reside during the day. After dark, on favourable nights, they ascend vegetation to feed and mate.
Apotrechus unicolor
(from Tepper 1892 Trans. R. Soc. S. Australia 15:167)
small size. brick-red colour, face brownish, rough, with horizontal folds, ocelliform spots absent. pronotum rust coloured, disk uneven. hind femora below with two spines towards apex. hind tibiae flat below. ovipositor very short, scarcely extending beyond the cerci. length of body male 35mm, female 42mm. length of pronotum male 7mm, female 8mm. length of hind femora male 14mm, female 17.5mm, length of ovipositor 5mm.
Fig. 49 from Brunner von Wattenwyl 1888
male found in wood heap 5/6/17 35mm body length
(from Rentz and John 1990 Invertebrate Taxonomy 3: 1053)
Overall colour straw brown except frons mottled reddish brown, clypeus white, labrum creamish white; genicular area of hind femur dark brown. Antennal scape and pedicel straw brown, contrasting with flagellum which is darker brown.
Male: Size very large for family, form very robust. Head with fastigium of vertex very broad, low, about 2.5 times as broad as scape, sides not raised or carinate. Eye elongate, slightly broader in median portion than in A. illawarra, sp. nov. Scape about as long as eye, with a distinct knob or swelling at base on internal margin; scape much longer than length of pedicel and first segment of flagellum combined; Frons rough, with minute, irregular punctures.
flagellum very thick basally, about twice as long as body.
Pronotum with surface mostly flat except in postero-lateral portion where there are 2 low callouses.
Fore tibia with 4 spines on anterior margin of ventral surface, 5 on posterior margin, the apical spine minute;
middle tibia with 4 spines on each margin of ventral surface, the apical of each minute, spines of fore and middle tibia positioned along distal four-fifths of leg.
Hind tibia without any spines dorsally; apex with 2 minute spurs dorsally, ventrally with 4 spines preceded by 2 elongate, subapical spines positioned parallel to each other on leg.
Hind femur bearing 2-3 small teeth (lectotype has 2 on one side 3 on the other); small teeth on each margin near apex.
rows of pegs on tergites 2 and 3 arrowed
Tergite II with 2 rows of pegs, the first of which is short and at nearly a 45 degree angle to the second; tergite III with 2 longer, more vertical rows of pegs.
Tergite IX (Figs 69, 70) not appreciably bulbate, apex weakly, shallowly divided; intercercal teeth short, stout, curved ventral and forward;
cerci elongate, erect, divergent.
Subgenital plate (Figs 71, 72) laterally with 2 distinct tubercles, central median portion broadly divided (as opposed to narrowly divided in A.illawara).
Female: Differs from male in following characters: size much larger, form more robust; apical abdominal tergites not modified; cerci relatively short, erect, divergent, subgenital plate (Fig. 74) short, apically very broad and truncate and with a distinct lip or rim; lateral portion feebly produced, with a pocket or pit at base. Ovipositor (Figs 73, 74) produced beyond tip of abdomen for a short distance.
18/9/13 female found on branch that fell from silvertop ash
Overall colour straw brown except frons mottled reddish brown, clypeus white, labrum creamish white; genicular area of hind femur dark brown. Antennal scape and pedicel straw brown, contrasting with flagellum which is darker brown.
A male and female of A . unicolor was kept in a container of sand and dry leaves and like A. iilawarra sp. nov. it showed no interest in burrowing in the sand but constructed shelters from dried leaves and twigs in which it resided during the day. The captive specimens made an audible rasping sound by rubbing the inner faces of the hind femur against the side of the abdomen when disturbed. This seemed to serve purely a defensive function.
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