RED AND YELLOW'—Rober t Webb, who lives at the north end of Ackerman Street, isn't going to water his lawn at night any more. That's what he was doing last week when this 2-foot-long coral snake crawled across his sidewalk just a couple of feet away. Webb killed the highly-poisonous snake with a broom handle. How can you tell if it's a coral snake? "Red and yellow, kill a fellow." The red and yellow bands touch.