Pharmacus Pictet & de Saussure, 1893: 301–302.
Pharmacus – Hutton 1896: 238. — Richards 1972: 154–156.
Pharmacus montanus Pictet & de Saussure, 1893.
‘ Pharmăcus ’ is Latin for ‘sorcerer’. The noun’s gender is masculine.
A genus of small to mid-sized cave wētā (adult body length 10 to 18 mm, typically around 15 mm) with a distribution limited to the high alpine regions of the South Island of New Zealand. Only found above tree-line, often above snow-line, at elevations as high as 2800 m a.s.l.
All species in the genus look similar to each other. While this makes it easy to characterise the genus, an examination of the adult male terminalia is often required for a reliable identification to the species level. A detailed description of the genus follows below; individual species descriptions focus on those traits that vary between species or that differ from the generic description.
HEAD. Oval in shape; glabrous except for maxillary palps and antennae. Frons with a pale median line and two dark stripes converging to the fastigium on either side (Fig. 7A, C). Eyes rounded, but with a straight inner edge facing the fastigium. Face generally mottled with dark and pale patches. Fastigium pointed and ending abruptly below; dark with pale patches on either side; divided by a deep median groove. Scapes of antennae approximately three times as long as pedicel. All parts of the antennae pale or reddish-brown and covered with fine setae, except for the rotating joints. No visible sexual dimorphism in scapes of antennae or any other head-part (Fig. 7). Maxillary palps pale, of varying length, with moderately dense covering of hair.
THORAX. Colour and tomentum on pronotum variable both between and within species. A pale, thin median line is generally present, although it may be inconspicuous (see Fig. 8). Lateral edges of pronotum with a pronounced rim and bent upwards in all species.
LEGS. Moderately long. Hind femora generally shorter than body; hind tibiae between 30% shorter and 10% longer than body in females, between 20% shorter and 20% longer than body in males. Coxae and trochanters mottled light and dark brown. Fore and mid femora and tibiae may be uniform pale or brown, or variegated; hind legs variegated. Fore coxae with a pronounced lateral anterior spine. Fore femora without linear spines above or below, but may be armed with one prolateral spine at the apex in some species. Fore tibiae armed below, generally with two linear spines on both anterior and posterior edge in all species. Fore tibiae armed with two long spines below (one prolateral and one retrolateral) and two short spines above (one prolateral and one retrolateral) at apex. Mid femora without linear spines above or below, but always armed with one retrolateral spine at apex. A prolateral spine at the apex of the mid femur may be present in some species. Mid tibiae armed below, generally with two linear spines on both anterior and posterior edge in all species. Dorsal linear spines on the mid tibiae are rare but possible. Mid tibiae armed with two long spines below (one prolateral and one retrolateral) and two short spines above (one prolateral and one retrolateral) at apex. Hind femora may be armed with linear spines below, but never with apical spines. Hind tibiae armed with an average of 22 linear spines above, of varying length, on both anterior and posterior edges (Fig. 9). The spines are fused to the shaft of the tibia and are not socketed or articulated (Fig. 4K). Hind tibiae with two superior subapical spines (one prolateral and one retrolateral), two superior apical spines (one prolateral and one retrolateral), two inferior apical spines (one prolateral and one retrolateral) and two inferior subapical spines (one prolateral and one retrolateral). Superior apical spines approx. 50% longer than inferior apical spines; inferior apical spines approx. 50% longer than superior subapical spines; superior subapical spines approx. 50% longer than inferior subapical spines. Hind tarsi with four segments; first and second segments with a pair of spines on distal end. First segment and occasionally second segment armed above with small, alternate dorsal spines, in all species except Pharmacus montanus. The length of the tarsus segments (ordered from first to fourth) is in a ratio of 9:3:1: 5.
ABDOMEN. Colour of tergites typically chequered, alternating pale and dark patches (Fig. 8). A uniform brown colour is common in adult Pharmacus montanus and in the nymphs of several species; a uniform black colour is common in both P. montanus and P. cochleatus populations above the permanent snowline. Dorsal median line generally visible but may be thin and inconspicuous. Tomentum variable both between and within species.
MALE TERMINALIA. Cerci between 15% and 20% of body length, pointed at apex, variable in colour, clothed in setae. The distal half is often visibly thicker than the proximal half (see Figs 5A–B, 10E, K, 11E, G–H). Styli short and stumpy, covered in sparse setae. The subgenital plate looks fairly similar in all species, broadly triangular, but enlarged in a spoon-like structure at the apex. The difference between species however is pronounced enough to provide the strongest character for species level identification (see Figs 10–11).
FEMALE TERMINALIA. Subgenital plate bilobed and rounded in all species. Ovipositor reddish-brown, straight or gently curved upwards at apex, terminating in a sharp point; relatively short (approximately two thirds of body length). Upper valve always smooth above; lower valve with 5 to 9 strong teeth at apex on ventral edge (Figs 12–13).
Nymphs generally look the same as adults, only smaller, which makes them readily identifiable as Pharmacus.