Genus Chaetoceras Handschin 1926.
This genus was erected for a species, Chaetoceras sarasini Handschin, from New Caledonia (Philippine Jour. Sci., XXX, p. 238, 1926). The following generic characters were given by the author:—“Body long and slender. Antennae more than twice as long as the body, underneath with long stiff bristles, sometimes as long as a joint. Furea broad, nearly twice as long as the body. Mucro smooth, not disarticulated from the dentes, with coarse teeth. Body covered with broad, dense serrated bristles.” He further remarks that the genus seems to connect the Paronellini with the Cremastocephalini.
In his work on the material collected by the. Mjöberg Expedition to Australia Schött (Arkiv. f. Zool., II, p. 22, 1917) resurrected the generic name Pericrypta Ritter, 1912, giving P. fasciata Ritter as the genotype, Ritter's other species P. sulcata having been shown to be really a species of Cremastocephalus (now Salina). Schött described Pericrypta mjöbergi from Australia. In my recent paper (Proc. Roy. Soc. S.A. 1934) I added two other species of Pericrypta from Australia, P. dandenongensis and P. lineata. From a study of these three species of Pericrypta and comparison with Handschin's generic characters of Chaetoceras there seems very little to separate the two genera, beyond the very long setae on the antennae and legs and the tendency for ciliated or plumose dorsal setae to broaden and become scale-like. Indeed in P. dandenongensis the longer antennal setae rather approach those of Chaetoceras in length. It would seem, therefore, that Handschin's genus may be better considered at not more than a subgenus of Pericrypta (Ritter) Schött, but until more material of the Australasian species is available it should stand. The new species described in this paper also differs from all the above species in possessing spined dentes, a character which may necessitate further separation.
Chaetoceras pritchardi n.sp. (Text-fig. II, a-e).
Description: Length to 3.0 mm. Colour yellowish with brownislt medial longitudinal stripe due to brownish setae and with light bluish or purplish pigmentation on head and body as indicated in Fig. 2a; legs and antennae purplish. Eyes 8 on each side on dark patches, equal. Antennae about twice as long as body, ratio or segments
I : II : III : IV = 60 : 80 : 45 : 100; the relative lengths somewhat variable but III always much shorter than IV, and IV much longer than III; III and IV distinctly annulated. Body-segments th. II : III : abd. I : II : III : IV : V : VI = 25 : 18 : 10 : 12 : 13 : 55 : 6 : 2; abd. V about 4 times as long as III. Legs long, elaws with a large outer tooth and two inner teeth; empodial appendage simple, without teeth, reaching distal inner tooth of claw; spur hair of tibiotarsus thick, spathulate and almost as long as claw. Furca as long as body; ratio of manubrium to mucrodens = 65 : 100; dens with numerous ciliated setae and a single row of spines which are simple, without apical scale-like lobes at apex; mucro not distinctly separated from dens, bidentate. Clothing of numerous ciliated or plumose setae which are very variable in length and shape, from the long clavate thoracic setae to the long pointed ones on the bodysegments; the shorter setae dorsally on the thorax and abdomen tend to broaden and become somewhat scale-like (ef. Fig. 2, e). The antennae on the lower surface and the legs carry a number of very long simple setae which often are almost as long as the segments themselves.
Localities: Among fallen leaves in native bush at Niger Bay. Hillsborough, Auckland, 22/12/32 (E. D. P.); Davies' Bush, Brookby, Manurewa, Auckland, 26/8/32 (E. D. P.).
Remarks: This very interesting form is closely related to the genotype from New Caledonia, but differs from it distinctly in the presence of the dental spines and in the absence of an inner angle to the empodial appendage. I have considerable pleasure in dedicating it to its finder.