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Kong one of the Evaniidae, and the larva of one of these is reported from elsewhere to be parasitic on cockroach eggs. But does this statement apply to the Hong Kong species of Evania? Or has there ever been any systematic study of this in Hong Kong?
Then look at the ravages from WHITE ANTS. Why, the money lost annually in Hong Kong from white ants alone would keep several first rate entomologists in the Colony studying the whole question of insect con- trol. True, the white ant is a difficult foc. I once said to a great entomo- logist that I thought he should find and introduce a parasite of the white ant to kill it off: but he assured me that no parasite of the white ant was known at that time. Perhaps one may be found or may be bred. No better field for experimentation could be found than Hong Kong. Dr. Howard mentions one curious fact about the white ant One most extraordinary thing about the diet of termites is that the younger individuals are fed largely on the excreta of the older ones, either from the surfaces of Each their bodies, or from their anal extremities.
individual, therefore, is a triple source of nourishment to his fellows he has to offer exudates from the skin, crop food from the mouth, and intestinal food, from the anus-and this mutual exchange of food appears to form the basis for much of the attachment that exists among the members of the Colony."
A foreign entomologist once told me that through this very practice of white ants he had found that they could be destroyed completely by feed- ing them on Paris green and other such substances. Does thus apply to the Hong Kong species? Or have any experimental measures of the kind ever been tried locally?
Then there are the MOSQUITOES. They have almost driven us out of some districts. True, we have made many efforts to keep them under control. Their breeding places have been greatly reduced, especially by the P.W.D. work in training the nullahs. But this is only one method of control aimed against a particular type of foe. But all mosquitoes are a danger and a curse, and there are still loopholes of escape. As an example, take the faulty or choked gutters on the roofs of houses. They are a favourite breeding place of some mosquitoes. But they are very difficult to get at; and any periodic adjustment or clearing over short periods, is very costly.
But there may possibly be other means of attack. What about the dragonfly? The training of the nullahs in Hong Kong has largely done away with the breeding places of the dragonfly. Every body must have noticed how much fewer the dragonflies are in Hong Kong than in the surrounding Territory. Now the dragonfly is a voracious enemy of flies. It "will eat one after the other thirty house flies without lessening' its voracity" (Howard p. 116). It also is reported to eat mosquitoes. suggestion has often been made to have an experimental breeding station for dragonflies. Why should it not be tried? It might be less costly than nullah-building, and even for the sake of mortality in houseflies it might be worth while. Then there is the possibility of parasitic control.
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parasite of the mosquito may yet be known-but there is room for unlimited experimentation.
If we only think of the number of persons in Hong Kong who have been ruined in health by malaria, and the far larger number whose efficiency has been lessened 50-80%, whose whole work and usefulness have been spoiled, whose temper has been soured, and whose object in life has been frustrated and all through malaria-we must feel eager that no effort should be spared and no channel left untried to clear out the mosquito. We have, of course specialists working on the subject, but would pay hand over fist to have two or three more employed.
Then take the HOUSEFLY—the typhoid fly as it is called. Walk through the native village of Cheung Chow or Tai Po Market (and they are two of the cleanest villages of the Territory) and look at the food exposed for sale. See if you can count the number of flies on one piece of salt fish or pork or sugar-cane. What is being done to control this mass of trouble- breeders?
Or take the BED BUG (Cimex lectularius). I had never seen a bed bug alive till I went to Hong Kong. Just after my arrival I took on the lectureship in Biology to the Hong Kong College of Medicine, and as wanted some specimens of various types of insects for a demonstration, I gave the coolie two collecting tubes and asked him to get me a few bugs. What was my astonishment on the following morning when he brought me the two tubes packed full-more bugs than I had thought would have been in the whole Colony! Yet I suppose these were all got from three or four wooden beds.
And then there are the SAND FLIES and the BOOK WORMS— but I might go on endlessly. There is only one thing for it-trained entomo- logical research of the most efficient and highly skilled type. It is a penny- wise-pound-foolish policy to allow cost to weight for one moment against It could not of course show an immediate return in such an urgent need. dollars and cents but this is all the more reason why foresight should be shown.
But there is another and almost personal interest to Hong Kong in this book. There is in it an entomologist's tribute to Dr. Frederick Muir and his great poineer work for the sugar-cane of Hawaii. Dr. Muir was well known in Hong Kong. Few men had tramped more of its hills and valleys, and none knew its insects (especially the Diptera) as well as hc. Indeed there must be few who had been over so much of the land surface of the earth, or could give such an interesting account of their pursuits. His was a wonderful undertaking. But we shall let Dr. Howard tell it :- I think that the story of Muir's efforts to find and to introduce into Hawaii an effective parasite of the sugar-cane borer is the best one of its kind of which I have any knowledge. The resourcefulness, the persistence, the heroic and long continued effort (crowned as it was at last with triumphant success) were so great that the story must be told here, even though briefly. The great enemies to the sugar-cane in Hawaii were the leaf hopper and
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May 1933.
The Hong Kong Naturalist.
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