1068 
LOCUSTS. 
(Acridium manilense Shiner.) 
It must always be borne in mind that the topographical features of 
the Philippine Islands are such as favor to a great extent the propaga- 
tion of the Philippine migratory locust. There are vast areas of waste 
land comprising both level and mountainous regions, and from all 
observations thus far made the insects repair, with a certain degree of 
regularity, to such regions, after having made depredations upon the 
small areas of cultivated land. It is certainly not possible that such vast 
hordes as at times appear in certain cultivated regions could gain their 
sole sustenance from tilled lands. 
The so-called’ locust fungus has been used since 1902 in experiment 
against these insects, but, save for a very meager positive result in the 
laboratory, practically all of the trials made have resulted negatively. 
This may be due to one of two causes, either that the fungus used became 
contaminated and lost in the processes of transfer or to the fact that the 
locust found here is not susceptible to the attacks of the fungus. 
During the past three years very accurate data have been secured 
with reference to the life history of these insects, with the important 
exception of their periods of disappearance from inhabited regions. 
Within a very few months it is hoped to establish an expedition which 
will have as its object the thorough exploration of waste mountainous 
regions for the purpose of further studying the locusts in their natural 
haunts. 
No accurate estimate can be made at present of the damage caused 
annually by locusts, but from the very incomplete returns we know that 
it is very great, the crops suffering most severely being rice and sugar 
cane. 
RICE INSECTS. 
Aside from locusts, rice is seriously affected by three other insects, 
the rice army-worm (Spodoptera maurita Boisd.), the rice stem borer, 
a recently discovered and as yet unidentified species belonging to the 
Pyralidex, and the tiatigao (Leptocorisa acuta Thunb.), an hemipterous - 
insect which causes considerable damage by attacking rice in the “milk” 
and sucking the juices from the young heads. 
The rice army worm, so-called because of the habit of the larve of 
traveling in companies, like Heliophila wnipuncta Haw., of the United 
States, has caused considerable loss, especially in the Provinces of Pan- 
gasinan and Tarlac, in Luzon. The stem borer has but recently come to 
my notice, it having been found as a larva on a rice grown at the Govern- 
ment experiment station in Manila from seed brought from North 
Carolina. The egg being laid near or upon the ligula, the tiny larva 
bores into the stem in the upper joint and by the time it is full grown 
