Preschoolers on a nature walk in Montgomery County yesterday were confronted and stung by a swarm of winged insects, sending 11 of the children to a hospital.

The children's injuries were not serious, and all were released from the hospital by yesterday afternoon, said the Rev. Currie Burris, pastor of Silver Spring Presbyterian Church, which sponsors the preschool program.

Fifteen children, ages 3 to 5, had been on the walk with adult leaders on a trail near Montgomery Knolls Elementary School in Silver Spring, said Pete Piringer, a spokesman for the county's fire and rescue service.

"One of the children disturbed a log and rolled it over, and some bees came rushing out," Burris said.

Others said the insects might have been those commonly known as yellow jackets. Bees and yellow jackets are often confused; bees generally are larger, with thicker, hairy bodies.

The children "were pretty scared, of course," Burris said. The school "has been open for close to 30 years, and we've never had anything like this," he added.

The school operates year round, Burris said, and the same nature walk has been held before.

Kathy Jones, assistant director of the preschool, was also stung "three or four times . . . trying to get the bees off the kids," he said.

"We're just so grateful that all the kids are okay," he said.