THE TROPICAL AGRICULTURIST. 
715 
There has been some correspondence between the Ceylon Government and a company desirous 
of starting Sericulture in Ceylon. It is unfortunate that the negotiations broke down. If once pro- 
perly started, this industry would be of great benefit to the native population. The rearing of 
silkworms is a work which the Sinhalese would soon learn, and which could be carried on in addition 
to their usual occupations, the cocoons being sold to central factories. 
Experiments in the destruction of termites (white ants) by the use of bisulphide of carbon 
have been conducted with considerable success. But the very limited supply of the chemical obtain- 
able in Ceylon has prevented the continuation of the trials. Three main shafts of a large ant-hill 
were plugged with the bisulphide, about half a pound in all being used, and all the openings closed 
with clay. Twelve hours later the nest was opened. A few living insects were observed close to the 
surface, but lower down the slaughter had been immense. All the comb-like material was blocked 
with corpses. Unfortunately the queen cell could not be found, so it is uncertain whether that most 
important individual was killed or not. Even if the poisonous gas failed to reach her, she would 
probably soon perish for want of attendance, and the mass of putrifying bodies would further poison 
the air in the lower chambers. The few individuals observed at the top of the nest were doubtless 
some that had been foraging at the time of treatment and had since returned. I feel satisfied that, 
if the bisulphide could be obtained cheaply in the Island, it would prove a most valuable agent in 
checking the ravages of white ants. 
Insecticides. — The difficulty of obtaining stock insecticides at prices that will allow of their 
being freely used has greatly interfered with the treatment of many insect pests. I have now made 
arrangements wdth a firm in Colombo to import and stock such articles as may be recommended for 
the purpose. 
E. ERNEST GREEN, 
Government Entomologist. 
3.-EEP0RT OF THE SCIENTIFIC ASSISTANT. 
I ARRIVED on the 28th June, 1900, and since that time have been engaged in an investigation 
of the floral and vegetative characters of the genus Diospyros. If time permits, the inquiry will be 
extended to the members of the other genus — Maba — of the Ceylon Ebenacese. 
The rarity of flowers and the occurrence of coloured woods (ebony, calamander, &c.) in the 
genus Diospyros had led to some confusion, and it is hoped that the present investigation will lead 
to a better understanding of the specific characters of the members included under this head. 
Hitherto my work has been confined to collecting the vegetative organs and to an analysis of the 
anatomical features of the seedlings and timbers yielded by the various species of this genus. 
Evidence has been obtained to show that in the details of the anatomy and disposition of the 
conducting tissues of the seedlings, specific characters are presented, and these will be used for 
purposes of classification as is now done in other natural orders by modern systematists. 
In studying the development of seedlings of calamander {Diospyros qucesita, Thw.), observations 
have been made which indicate one of the causes threatening the extinction of this valuable timber 
tree, and these, together with remedial suggestions, will be subsequently published. In analysing 
the black and variously mottled timbers obtained from these plants, the cause of discolouration has 
been determined, and experiments have been initiated witli the object of inducing a blackening of 
the timber in the peripheral sapwood. 
In consequence of the slow rate of growth and evergreen nature of these trees, it is difiicultto 
obtain an intelligible interpretation of their age, and experiments have been organized at Hakgala, 
Badulla, Anuradhapura,and Peradeniya, which will assist us in our efforts to obtain a correct elucidation 
of the seasonal anatomical peculiarities of these and other tropical timbers. In these experiments 
upwards of 300 observations are being taken every month, and by this means we shall be able to 
determine what tissues have been formed during any particular period. These facts will then be 
correlated with the general behaviour of the plants and the climatic conditions under which they are 
growing. When the flowering period arrives a thorough re-investigation into the morphology of the 
repx'oductive organs will be undertaken and correlated with the timber yield of each species. As 
there is so much doubt in this direction an organized system of collecting will probably be instituted. 
The Forest Department of Ceylon has generously forwarded new and rare specimens, and 
the officials of the Botanic Gardens at Sibpur, Madras, Saharanpur, Singapore, and Mauritius have 
likewise given every assistance. 
H. WRIGHT. 
