(Pl. VI., figs. 1–13.)
An adult female of this spider was contained in a small collection made in
Canterbury, New Zealand, several years ago, and kindly given me by Dr. Ll. Powell, of Christchurch, N.Z. In a subsequent collection from Waikato, N.Z., kindly sent by Captain Hutton, there were one or two others (females also) of the same species. Upon one of these (a very small example) the above new genus was founded by Dr. L. Koch, to whom I had transmitted the specimen for examination. More recently still, Captain Hutton has forwarded me an adult male and female of it found by Mr. H. H. Travers at the Chatham Islands, N.Z. The adult male nearly resembles the female in colours and markings, but is very much larger than either of the females I have yet seen, and differs from them notably in the development of the falces; in fact, the whole spider affords such a good example of the different points of detail in the general structure of the Araneidea, that I have decided to figure it in the present instance for the purpose of illustrating the structural features of spiders remarked upon in the previous pages.
With regard to the genus Cambridgea, founded upon this species by Dr. L. Koch, I was at first rather doubtful myself as to its distinctness from Argyroneta, Latr.; as, however, that able author still adheres to his opinion on the point, I have given this spider here under the generic name which he has done me the honour to confer upon it, though not having myself yet been able to compare it critically with Argyroneta. The following are the measurements of the different examples that have as yet come under my notice :—
Female adult (type of genus and species), Waikato, N.Z.; length, 3.5 lines.
" " " " Waikato; length, 5 lines.
" " " " Canterbury; length, 7 lines.
" " " " Chatham Is.; length, 8.5 lines.
Male adult " " " Chatham Is.; length, 10.5 lines.
This great variation in size is also a strong character in the genus Argyroneta; as also are the development of the falces in the male, and the existence of the supernumerary spiracular orifices indicated in f. 2tt., and f. 3p.
The following is a detailed description of the male :—
Cephalo-thorax oval, moderately convex above, constricted laterally forwards, and rather truncate at its fore extremity; it is of a light reddish-yellow brown colour, with a broad lateral band of a much deeper hue on either side, and also a similar longitudinal central one, divided almost throughout its length by a fine light reddish-yellow line. The height of the clypeus, which is nearly vertical, is less than half the facial space; the surface of the cephalo-thorax is thinly clothed with fine adpressed light-coloured hairs, with a few prominent bristles in the ocular region.
The Eyes are of tolerable size, but scarcely differing from each other in that
respect. They are in two curved rows, forming a transverse oval figure, about double as long as it is broad at its broadest diameter. The eyes of the hinder row are equi-distant from each other. The fore central eyes are rather nearer together than each is to the lateral of the same row on its side. Those of each lateral pair are seated slightly obliquely on a not very prominent tubercle, and are near to each other, but not contiguous.
The Legs are long and tolerably strong; their relative length is 1, 2, 4, 3, and they are furnished with spines (not very long nor strong), and with, numerous—some nearly erect—hairs of different lengths. The colour of those of the two foremost pairs is yellow-brown, the femora and genuæ being darker than the rest, and with a very faint indication of a paler annulation both on the femora and tibiæ. The two hinder pairs are similarly coloured, but have two distinctly marked yellow annulations on each of the femoral and tibial joints; each tarsus terminates with three curved claws; the superior ones pectinated beneath the hinder half; the inferior one much the smallest, and strongly bent downwards near its base, where it has one or two teeth.
The Palpi are rather long and slender; they are of a reddish-yellow brown colour, the basal part of the radial joint being pale yellow brown, shading off into the redder part. The humeral joint is bent inwards; the radial is more than double the length of the cubital joint, and rather strongest at its fore extremity, near the outer side of which are two small apophyses; that nearest the base of the digital joint is the largest, of a flattened form and truncate extremity, the other (behind it) is sharp pointed, and of a somewhat tooth-like form. There is also a small prominent point beneath the larger apophysis above-mentioned. The digital joint is small, oval, but its extremity is greatly produced in a long cylindrical form, being a greatly exaggerated example of a somewhat similar form in Argyroneta and Tegenaria. The length of the digital joint considerably exceeds that of the radial and cubital together, being about equal to that of the humeral joint. The palpi, like the legs, are furnished with a few slender spines and long hairs; of the former are several longish conspicuous ones on the digital joints. The palpal organs are contained within the oval basal part of the digital joints; they consist of a simple whitish oval lobe, with a red-brown corneous lateral margin, probably an independent, though closely adhering, spine, but this I could not ascertain satisfactorily; there are also a sharp-pointed dark red-brown spine on their inner side, and a stronger obtuse corneous projection near their extremity, and a small one on the outer side.
The Falces are long, strong, divergent, and projecting forwards; their length is very nearly equal to that of the cephalo-thorax; the fangs are long and strong, and beneath them are several strong sharp teeth along the inner side of the falces, which are of a deep rich reddish chestnut brown colour, and
furnished above with short strongish hairs; the fangs are of a still darker hue than the falces.
The MaxillŒ are strong, straight, enlarged at their extremities, where they are rounded on the outer, and obliquely truncated on the inner-sides, the inner edges curved somewhat over the labium, which is of an oblong form, deeply notched or hollowed out in a circular form at its apex; these parts, as well as the sternum, which is of ordinary form, are of a dark red-brown colour, the labium being rather the darkest. The maxillæ are furnished with strong bristly hairs; those on the inside, and beneath their extremities, forming strong tufts. The labium and sternum are also furnished with hairs, and these are less strong than those on the maxillæ.
The Abdomen is of moderate size and oval form. Its fore part (looked at in profile) is high, and slopes gradually to the hinder extremity; the upper part and sides are of a dull yellowish colour, marked chiefly on the sides and outer edges of the upper part with black-brown spots and short striæ. There is also, on the fore part of the upper-side, an indication, by means of a dark, irregular margin, of a longitudinal central oblong marking, pointed at its hinder extremity, and with an obtusely angular prominence near the middle of each side—the hinder part of this marking is followed by other dark, irregular markings to the spinners. The under-side is suffused with dull brown, laterally bordered with a yellowish, ill-defined stripe, along which is a row of small, rust-red spots; there appears to be some variation in the markings on the upper side, one female being far more marked with black-brown, and having some oblique pale stripes on the sides. Besides the ordinary spiracular openings, there is, on either side, another narrow, reddish slit, or opening, a little above the usual one when the spider is looked at in profile (f. 3p). Also, between the large spiracular plates or opercula are two other still smaller openings of a reddish hue (f. 2tt), all of which probably open into spiracular tracheæ. These openings have been observed also in Argyroneta; and in the Drassoid genus AnyphŒna analogous ones have been found between the ordinary spiracular plates. The spinners are very short; those of the inferior pair being the strongest, and of a paler hue than those of the superior pair.
The colours of the female are clearer, and the markings better defined than those of the male above described; their general character, however, is tolerably similar. The figure given (l.c. supra) by Dr. L. Koch, of the female, is excellent. I have not been able to learn anything of the habits or economy of this fine and remarkable spider.