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There were just 17 wild Schaus swallowtail butterflies in existence, all on a small island, when zoologist Thomas Emmel began actively breeding them in a laboratory and kitchen.

Now, with their numbers soaring, the butterflies are being reintroduced to their native southern Florida habitat and could be off the endangered species list in two years.The remarkable comeback of the brown-and-yellow insect, speckled with blue and red dots, is more than just successful science. The delicate but hardy butterflies have survived toxic pesticides, Hurricane Andrew and swarms of predatory birds.

Interior Secretary Bruce Babbitt will be on hand Monday when Emmel, of the University of Florida, releases about 250 Schaus swallowtails in a state-owned park south of Miami.

This is the second year Emmel is reintroducing the butterflies into the wild, and it might be the last if another 800 to be released later this spring do well.

"It's a real milestone," said Jane Tutton, a biologist with the U.S. Fish and Wildlife Service.

The Schaus could be reclassified as a threatened species or taken off the list altogether by 1998, she said.

In the early part of the century, the Schaus was abundant in the Florida Keys, especially Key Largo where "butterfly collectors could see hundreds in a day," Emmel said Thursday.

The butterfly, which has a 41/2-inch wingspan and lives for just three days, was one of southern Florida's main wildlife attractions and was prized among collectors who paid top prices - up to $400 per specimen.

Then in 1972, Monroe County began spraying the Schaus' leafy habitat with two pesticides, Baytex and Dibrom, to control mosquitoes. Field tests later showed that the chemicals, which Emmel says were used at a concentration 4,000 times greater than necessary, nearly wiped out the Schaus and 50 other insects from the Keys.

By 1976, the Schaus was listed as threatened under the Endangered Species Act and eight years later was upgraded to endangered.

Things began looking up for the butterfly when the use of Baytex was banned as a pesticide in the state in 1991 and new regulations were established for Dibrom. Almost immediately, its numbers began to rebound - reaching nearly 1,000 by 1992.

Emmel nevertheless started a captive breeding program in June 1992 at his Gainesville laboratory and in a graduate student's kitchen. He had no idea the 100 eggs he started with would become the future breeding stock of the entire species.

Two months later, Hurricane Andrew tore across southern Florida, killing all but 17 adult Schaus butterflies known in the world. All 17 were on Elliot Key in Biscayne Bay.

Emmel's project took on added urgency. More federal, state and private grants allowed him to move some of the larvae from the kitchen to new facilities.

"We felt very good about the serendipity of the whole thing," Emmel said. "We felt that at that point, the butterflies in Gainesville were the only significant species."

By early 1995, Emmel had enough butterflies to reintroduce about 760 pupae into the wild. They did well, until a series of cold fronts in the spring stalled the northward migration of warblers over the Keys.

"We lost 60 to 90 percent of the population to birds," Emmel said. "We realized we had to do a second cycle of captivity."

It is that second cycle that is to be released Monday.

"It's not just listing a species (as endangered) and watching it die," Emmel said. "But it's restoring it and bringing it back so the public can enjoy it."