Insects:

The number of species known to occur in New Zealand is approximately 10,000. On the basis of a world census (1,000,000 species described and 2,000,000 species estimated), a figure of about 20,000 species may be close to the actual number for New Zealand. The last complete census of New Zealand insects was compiled in 1926 when the total was 8,150 species. This was a fair approximation although many undescribed species were included in that number. Some orders have been studied extensively since that time and, as a result, the number of species known has increased. The groups which have been most seriously studied in recent years are the spring-tails, wetas, aphids, scales, bugs, caddis flies, beetles, flies, and moths. Catalogues of species have been compiled in recent years for Diptera, Coleoptera, and Trichoptera.

Spiders:

A census of species in 1946 revealed that 304 species were known. Since that date some additions have been made and the total number of species now known is approximately 390.

Mites:

Ninety-nine species were listed in 1952. Lack of serious study in many groups of mites makes it apparent that the number occurring in New Zealand may well be far in excess of 100.

Harvestmen:

Recent study of this group has revealed a fauna of more than 160 species.