482 "General Notes. [May 
spraying will fully compensate for the small expense of the 
Paris-green application. This expense, when the spraying is 
done on a large scale, with suitable apparatus, only once or 
twice a year must fall below an average of ten cents a tree. | 
On the Life-History of a Dipterous Parasite of the Silk- 
worm.— [In the new journal published by the Imperial University, 
Japan,’ Professor Sasaki gives a very important paper on a dip- 
terous parasite of the silkworm. Aside from the economic bear- 
ing*of the paper, it is of interest to entomologists generally as 
giving a careful account of the habits of a parasitic insect which 
is peculiar in its mode of attack. 
The so-called “ Uji” disease, caused by the larva of a dipterous 
insect, Ugimya sericaria, plays terrible havoc among the silk- 
worms reared in May and July. When the silkworm is once 
infested by this parasite it dies either before or after it spins a 
cocoon; in the latter case the maggot eats its way out of the 
cocoon, thus leaving a round hole in it, with the consequence of 
making it unfit for reeling. In the spring or May brood of silk- 
worms some fifty to seventy per cent., or in extreme cases eighty 
per cent., are attacked by the parasite, and the damage done is 
correspondingly great. 
Fatal as the “ Uji” disease is to the silkworm, no systematic 
observations have hitherto been made on the habits and life- 
history of the maggot; but in this paper the insect is described 
in each of its stages, and considerable attention’ is given to ana- 
tomical features. We will notice, however, only that part which 
relates to the habits of the insect. 
The adult flies generally begin to appear in April. From this 
time to the middle of June they frequent mulberry-bushes. The 
eggs are laid on the under surface of the leaves, in close contact 
with the ramified veins. The eggs are fastened to the leaves and 
eggs laid upon leaves in the month of May, if undisturbed, will 
remain alive during the month of June, but later they are de- 
stroyed by the severe heat of the sun. At the time when the 
deposition of the eggs takes place most abundantly the silkworm 
is in its third or fourth moult. The eggs are taken into the body 
‘the silkworm at this time with its food. The small size of the 
egg and the hardness of the shell protect it from injury by the 
_ Jaws of the insect. 
_ In one to nine hours after the eggs are introduced into the 
digestive canal of the silkworm they hatch. The young larva 
“measures 0.3 and 0.2 millimetre in length and.breadth respec- 
tively. Its smaller anterior end is provided with a horny-hooked 
* Journal of the Col Science, Imperial University, Japan, vol..i., Part I. 
na S E T e 
