A New Beetle of the Genus Mecodema.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 74, 1944-45, Page 408

A New Beetle of the Genus Mecodema. By E. Fairburn. [Read before the Canterbury Branch, September 3, 1941 (communicated by S. Lindsay); received by the Editor, November 24, 1944; issued separately, March, 1945.] The following addition is proposed to the described beetle fauna of New Zealand:—   Sub-order: Adephaga.   Super-family: Caraboidea.   Family: Carabidae.   Sub-family: Carabinae. Mecodema allani n.sp. Plate 59. Moderately elongate and broad; subdepressed. Head, thorax, and underside of body shining black. Elytra dark chocolate colour rather dull. Legs, antennae, and four basal joints of the tarsi dark piceorufus. Apical joints of the antennae and tarsi distinctly paler. Labial and maxillary palpi red, with the apical joints slightly dilate at the apex. Labrum dark red in centre; angles paler. Head, including the prominent eyes not as wide as the thorax. On the forehead, two large depressions extend from the vertex in a line with the middle of the eyes, to a point a little in advance of the antennal insertion. Each of these depressions is indistinctly divided in two by a slightly raised transverse ridge. The hind depressions are almost circular and contain several conspicuous radiating striae. The front ones are somewhat irregular in shape and almost smooth. From the front edge of each, three rather deep striae proceed longitudinally almost to the front margin of the forehead. There is a similar stria in the centre and several shorter and shallower ones between this and the lateral ones. There are also two or three slightly curved, transverse striae connecting the two hind depressions. The rest of the forehead is raised and smooth with minute punctures. There are several irregular striae on the sides, extending from the inner margins of the eyes to the antennal insertion. There is one setigerous puncture on the inner side of each eye, and one at the base of each mandible. The whole of the back part of the head is coarsely and rugosely punctured, many of the punctures being confluent. Labrum sub-truneate in the centre with well-rounded angles. There are about five long setae along its front margin, and a row of shorter ones on the angles and sides. Mandibles coarsely and obliquely wrinkled for about two-thirds of their length with an obtuse tooth at the base. Antennae pubeseent from the fifth joint onward. Basal four joints shining, the first with one long setae on its upper surface, at about two-thirds of its length. Second with about two, and the third and fourth with several arranged round the apex. Pro-thorax 8½ mm. wide by 4½ mm. long in the centre. Apex almost subtruncate, being only slightly incurved. Base sinuate, rather strongly incurved at the centre, and with a short sinuation just inside the hind angles, making these project slightly backward. Both the apex and the base have a fringe of ciliae extending right across

Mma allani Fabun n. sp.

their margins, central line shallowest in the middle, reaching the base but ending in a well-marked curvate depression behind the apex. Just in front of the middle, and midway between the central line and the margins, there are two large, shallow depressions, one on each side, appearing in some lights to connect with the outer ends of the frontal depression. The sides of the pro-thorax are depressed just inside the apical angles, making the marginal channels appear rather wide at this point. Basal depressions large and deep, and dull with dense minutue sculpture. Marginal channels sub-crenate and reflexed, with a row of setigerus punctures along their edges. From behind the apical angles which are well rounded, the sides are nearly straight for about half their length, and from thence strongly rounded to the short straight portion in front of the basal angles. The whole surface is covered with faint transverse lines, and there is a row of short longitudinal striae extending almost right across the basal and apical margins. Elytra oval, rather broad, with moderately well rounded sides and only slightly convex. Marginal channels rather wide, reflexed and entire from base to apex with a row of several shining tubercles each with a puncture in its apex. The first, third, and fifth interstices are a little raised and definitely wider than the others. The seventh is conspicuous and defines the disc. It is narrow, sharply raised, and shining, and is thus in marked contrast to the rest of the surface. Between the suture and the seventh interstice, there are six rows of serial punctures. Between the seventh interstice and the marginal channel there are three more rows of coarser sub-serial punctures separated by two more or less interrupted interstices, this sculpture becoming very much coarser and more confused from the shoulders of the elytra nearly to the hind femora. The whole of the surface between the seventh interstices and the suture is covered with minutue sculpture consisting mostly of fine radiating and transverse lines. From the top of the posterior declivity the elytra are quite opaque and almost smooth, although traces of the serial punctures can be seen almost to the apex. Scutellum triangular, its hind margins raised and smooth, with the central portion deeply depressed. Underside of the head coarsely sculptured with short, mostly transverse rugae, except the gula, which is nearly smooth and shining. Wings of the mentum with finer rugae and a few punctures, tooth rather small. Prosternum nearly smooth with faint transverse lines and a few scattered punctures. The portion between the anterior coxae deeply grooved in the centre with obtusely raised borders. Flanks of the prosternum closely and coarsely punctured. Mesosternum nearly smooth, rather small and with a deep, curved channel between the intermediate coxae. Metasternum with a deep transverse depression across the centre. The front half obtusely raised, with a sharp projection between the intermediate coxae. Hind part nearly flat with a fine longitudinal stria in the centre. Its whole surface is covered with fine rugae running in different directions. Basal three abdominal segments densely sculptured with fine irregular wrinkles. The apical ones almost free of sculpture and shining. All the segments have a rather large puncture-like depression close to each side.

Legs rather long and slender. Femora with a few large scattered punctures. Tibiae very slightly curved, with fine setae on the lower edge and coarser ones on the upper. Apical spurs straight and moderately well developed. Claws of the terminal tarsal joint long and slender, only moderately curved. Length, 33 m.m.; width, 10 ½ m.m. Described from two specimens of uncertain sex, which were discovered by Dr. R. S. Allan, of Canterbury College, in a beech-clad valley between Mt. Horrible and Mt. Misery, near Cass, Canterbury, on January 19, 1938, and in whose honour I have great pleasure in naming this fine species. Type and paratype in Canterbury Museum; topotypes in my collection. Note: In M. laterale from the Hollyford Valley, which without doubt is the nearest ally, the elytra are quite black, with coarser sculpture on the disc, very much more so near the sides, the seventh interstice being more or less encroached upon by the coarse punctures. The alternate interstices instead of being in the form of slightly raised costae, are flat and hardly different from the others. The longitudinal striae on the front of the head also differ, being more pronounced and more equally spaced without any wide spaces between them. These differences in colour and sculpture are quite consistent in all the specimens of both species which I have examined.