THE TROPICAL AGRICULTURIST, 
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to be undescribed, but specimens have been sent to England for determination. The caterpillar 
may be recognized by the black head and second segment, the hinder parts being of a pale yello-wish 
tint. It conceals itself beneath galleries composed of silk and sawdust-like pellets of excremen- 
titious matter. The resulting moth is of a pale gray colour with minute black specks on the front 
wings. It measures about one inch in expanse. 
A short visit was paid to Kurunegala in September. This was partly to visit a cacao estate 
suffering from an attack of Tlirips, an account of which insect is given below ; and partly to examine 
the feverish parts of the locality in connection with the Mosquito-malaria Theory. Though, from 
the shortness of the time at my disposal, the larvse of Anopheles (the particular genus of mosquito 
associated with this disease) were actually captured in only one pool, I satisfied myself that the 
available breeding places of the insect were practically unlimited, and that it would be quite hopeless 
to attempt to exterminate the mosquito by either obliterating or chemically treating the 
Anopheles pools. The large extents of paddy fields alone would be sufficient to keep up the supply 
of mosquitoes. I am of opinion that preventive measures — i.e., protection against the actual bite of 
the mosquito, coupled with the removal of the principal source of infection by the enforced medical 
treatment of every case of malarial fever, is the only rational course of action. The Mosquito-malaria 
question is discussed more fully elsewhere in my report. 
A third tour, occupying one week early in November, was made in the Kelani Valley district. 
Many tea estates were visited, a meeting of the local branch of the Planters' Association was attended, 
and advice was given to the planters with reference to Helopeltis and other insect pests. 
The past year has not been marked by any very stai'tling outbreak of insect pests, though 
many cases of more or less serious injury, due to insect agency, have been observed and recorded. 
The following are some of the principal species that have attracted attention : — 
Heterusia cingala, Moore. — The caterpillars of this moth, locally known as " Red Slug," were 
prevalent in the Lunugala district in April, where a considerable acreage of tea was completely 
defoliated. Fortunately the damage was of a temporary nature. The caterpillars were collected and 
destroyed in large numbers, and in some cases the fields were heavily pruned and the prunings 
burned. Similar damage was reported from Rangalla in June. During my tour in the Kelani Valley 
district the caterpillars were observed very commonly on the tea, though no serious injury had been 
noticed there. It is, however, a dangerous insect to neglect, and Avhenever the caterpillar is seen 
seai'ch shoxild be made for the rest of the brood. 
The " Croton Caterpillar'''' {Amyna selenam2yha, Guen.) — Croton oil plants in both the Matale 
and Peradeniya districts sufiEered rather severely from this caterpillar, repeated broods following 
each other in rapid succession, devouring the fresh foliage as fast as it was produced. In Matale 
the principal attacks were in the months of January and June, while a fresh outbreak was reported 
in December. The pest was observed in Peradeniya in July, only after it had reached its crisis. 
Experiments were conducted with insecticides, some of the trees being sprayed with Macdougall's 
insecticide wash, and others with a preparation of arsenate of copper sold under the name of " green 
arsenoid." It was noticed that the former, applied in the proportion of 1 pound to 4 gallons of water, 
caused the almost immediate death of the caterpillars ; but experim-nts with the arsenoid, which acts 
through the alimentary system, were negative, being vitiated by the fact that the caterpillars were 
already dying ofE from a bacterial disease. Thie pest did not reappear on this plot of croton trees. 
" Nettle Gruls." — Several species of these stinging caterpillars have been noticeable during the 
year. The species responsible for most damage appears to have been Natada nararia, Moore, which 
was very destructive to tea in the Passara district early in the year. Over 100 acres of tea on one 
estate were completely defoliated, and hundreds of coolies were employed in collecting and destroying 
the insects. 
The larvae of Thosea cana. Walker, were received from Elpitiya ; Thosea recta, Hampson, 
from Morowak korale and Yatiyantota ; and SiKitulifimliria castaneiceps, Hampson, from several 
parts of the Kelani Valley. The first three species have been fully described in my circular on 
"Some Caterpillar Pests of the Tea Plant." The fourth has only recently attracted attention as a 
tea pest. It is a small and inconspicuous grub, of a chocolate brown colour, with a reddish saddle- 
shaped mark on the middle of the back and a few yellow spots. Though belonging to the family of \ 
"nettle grubs," this particular species is unprovided with the usnal urticating spines. The cocoon 
is very small, broadly oval, smooth and compact. The male moth is uniform dark purplish brown, 
with indistinct darker transverse bars across the fore wings, the expanded wings measuring just 
half an inch. The female moth is rather larger, measuring three quarters of an inch across the 
wings, and is of a much paler shade of brown. 
If left to their own devices, any of these caterpillars may suddenly appear in such numbers 
as to prove a serious pest. The only safe way to treat them is to take them in time, which is when 
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