Ecology

N. serratum and T. crassicruris are widely distributed throughout the Chatham Islands, and during the 1954 Expedition specimens were collected from South East Island, The Sisters, the south-east coast of Pitt Island near Glory Bav, and from Waitangi and Kaingaroa on Chatham Island. In 1924, specimens were also collected from Ouwenga and Mangere Island. Most of the wetas on the 1954 Expedition were collected from South East Island and the Sisters, largely because of the untouched conditions of the surroundings. T. crassicruris occurs in rotten logs and dead trees, is nocturnal in its habits, and is more generally distributed than N. serratum, which appears to be restricted to those areas inhabited by petrels.

South East Island is covered with coastal scrub, with little undergrowth, and is sheep infested T. crassicruris was found in and under logs and fallen branches, while N. seratum occurred under stones and in the burrows of storm petrels, broad-billed prions and mutton birds.

On the Sisters the soil is soft and peaty and riddled with burrows, there being little surrounding vegetation except hard fern and Cotula renwicki. T. crassicruris was found to inhabit rotten logs, while N. serratum was found under large stones half embedded in the soil, in association with large skinks, beetles and earwigs. The dark, humid burrows of mutton birds and prions also yielded specimens of N. serratum. A number of immature specimens of N. serratum were collected and found to be far more abundant than adults on the island.

The fact that N. serratum has not been recorded from Chatham Island is probably due to the inaccessibility of the petrels' nesting places, which has prevented the burrows from being visited by members of the various expeditions. At Waitangi and Kaingaroa in 1954, collecting was only carried out around the landing area.