Special to The New York Times.

HAVANA, Oct. 6--A new tax of 25 cents a 250-pound bag of raw sugar will be imposed on sugar produced by mills in Cuba to finance the campaign against the rebels, according to Dr. Anselmo Alliegro, President of the Senate.

Dr. Alliegro said he had called the Senate into session for next Wednesday.  There is no doubt that the tax will be approved.

The present tax on raw sugar is 27.5 cents a bag.