NATURAL HISTORY
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of special interest is the Hong Kong newt, which has not been record- ed anywhere else in China.
There are just over 200 species of butterfly in the Colony. Of the many moths two are outstanding for their size. These are the Atlas and Moon moths with wing spans of nine and six inches respectively. Apart from butterflies and moths there is a great variety of insects, many brilliantly coloured. They include many species of dragon fly and damsel fly and metallic-coloured beetles and solitary wasps. The beautiful Candle Fly or Lantern Fly has delicately coloured wings like those of a butterfly, but is more closely related to the cicada. It lives on lychee trees and is remarkable in that its forehead is almost as long as its body, hence the Chinese name which trans- lated means the elephant-nosed bug. The adults of several species of cicada emerge during spring and summer. They range from the rare three-and-a-half inches Tacua to the small grass cicadas less than half an inch long.
Land molluscs of note are the Giant African Snail, measuring about five inches long, which was introduced (and is now a con- siderable pest), and a large black slug, Veronicella, a species suffi- ciently distinct from all other slugs to be placed in a separate family.
MARINE LIFE
Marine life in Hong Kong waters is exceedingly diverse in variety, form and colour. It used to sustain a profitable inshore fishery, as the Yellowtail (Seriola quinquilineata), Mackerels (Scomberomorus species), Yellow Croaker (Pseudosciaena arocea) and a number of other schooling species appeared seasonally in commercially ex- ploitable quantities. In the course of fisheries development, however, the abundance of these resources (with the exception of certain isospondylous fishes) began to diminish-possibly due to an in- creasing disturbance of the local marine environment. The full extent of Hong Kong's marine fauna is difficult to assess, but the diverse varieties of fish, crustacea, cephalopod, mollusc and seaweed in- dicate that the number of species involved is certainly very high. The discharge of the largest freshwater system in South China to the west, and the prevailing Taiwan Current from the north-east, have created a situation where the westerly sector of Hong Kong has a predominantly brackish water fauna, while the eastern sector has a genuine marine fauna. A notable marine animal which has been successfully introduced in the Deep Bay area is the Japanese oyster, Crassostrea gigas. It is now being cultivated.