SANTIAGO, Chile (AP) _ The government has set legal traps to halt a booming export trade that is endangering exotic species of lizards, frogs, snakes, beetles and spiders, some of which fetch hundreds of dollars in U.S. pet shops.

''Several of these species are considered highly vulnerable, threatened with extinction,'' Leopoldo Sanchez, head of the government's Agricultural Service, said in a recent interview.

Chile has just amended a 63-year-old wildlife law, issuing a set of regulations that ban the export of some species and impose severe restrictions on others. The decree establishing the regulations is moving through the bureaucratic channels and is expected to be enacted within days, officials say.

Sanchez admits enforcement will be difficult.

''We have a tiny staff and a very limited budget,'' he said. ''But we are lining up the help of rural police, forest guards, the navy and 150 voluntary wildlife inspectors throughout the country.''

Jaime Vicens, director of the government's Division of Renewable Natural Resources, said the new regulations were prompted by ''an explosive increase in the capture of these species to be sold as pets, especially in the United States and Europe.''

A spider, a snake or a colorful lizard may sell for up to $300 in pet shops in those countries, according to Vicens.

''Projections for this year show that up to 500,000 spiders, snakes, lizards, iguanas, frogs and others would be exported this year without these restrictions,'' he said in an interview.

As an example, he mentioned the arana pollito, or chicken spider, a brownish large, hairy spider which is totally harmless.

He said 1,819 aranas pollito were legally exported in 1985, some 44,000 in 1990 and 39,150 during the first quarter of 1991.

Among other newly protected species are a giant, multi-colored beetle called mother of the snake, and several varieties of snails, beetles and scorpions.

Sanchez said the decree establishes special exemptions to allow the capture of any of the animals or insects for research purposes.