Be careful about what you swat in in the next few days in San Francisco.
San Francisco recreation and park officials plan to release 22 pregnant mission blue butterflies in the Twin Peaks area today in an attempt to boost the endangered species' population.
U.S. Fish and Wildlife Service spokesman Al Donner said more than 100 of the nickel-size butterflies lived in the Twin Peaks area in the 1980s, but now he estimates there are only a few left.
The Fish and Wildlife Service permitted biologists to catch 22 of the butterflies, classified as plebejus icarioides missionensis, from the hills in San Mateo County and bring them back to San Francisco.
With a name like that, it's no wonder they're known to most as the mission blues.
They will be released in an area that contains the flower Lupinus, and Donner hopes they will lay their eggs and "live their pretty little lives and replenish the population."