Dear Reader:

On my street, in my town, on any given evening, the fireflies emerge at dusk. Individual dots of light dart out of the bushes and grass in vertical ascent as if to greet the night’s stars. Each bug will flash only an instant, but long enough to leave a smear of amber against the thickening sky.

I am not an Illinois native and fireflies are something unique for me. I remember once in Michigan my grandfather caught one in a jar. Neither my brothers nor I had ever seen one. “Look, look!” he said excitedly in broken English. “They blip-a. Blip-a, blip-a!”

Stand out in your yard some night and look down your block. At any given moment you may glimpse scores of fireflies flashing, not as individuals, but in unison as if by prior arrangement. They say the bugs do this to attract a mate. Perhaps something deep within their genetic memory signals the precise moment to be seen. But it’s still not terribly hard to suspend disbelief and imagine not a plurality of individual fireflies but a single intelligence at work, choreographing an intricate ballet of light.

The performance is free on any summer evening. Except those nights the Mosquito Abatement District is at work.

The purpose of Illinois’ Mosquito Abatement Districts is to exterminate mosquitoes. My town, Glenview, is protected from its mosquitoes by the North Shore Mosquito Abatement District. Its method is pesticides. On any given evening a district employee might be in my neighborhood, on my street, at my house, spraying pesticide from the back of a pickup truck.

The pesticide, as of July 1993, is resmethrin–a synthetic pyrethroid insecticide. It is a toxin that attacks the central nervous sytems of insects. Resmethrin does not discriminate. It kills mosquitoes. It kills beneficial insects, including honeybees. It kills harmless insects. Resmethrin kills fireflies. I know. I’ve watched it happen.

The brand name of the poison is Scourge. Scourge, the manufacturer boasts, “knocks their legs off.” If the dose is not lethal, the bugs lose their legs, “inhibiting their ambulatory and mating abilities.”

The district might be spraying my neighborhood any night it deems mosquito populations too high. On those nights I see the fireflies not engaged in their nocturnal dance but on the pavement, flailing, distended abdomens still blip-a, as if the choreographer had gone inexplicably mad.

I found out about the North Shore Mosquito Abatement District the hard way: my family went out for a walk on a night they were spraying. The following day I learned the state systematically spreads pesticides throughout our residential neighborhoods to keep people from being bit by mosquitoes. If I had been warned of this before coming to Illinois I would not have believed it. I guess now it’s our little secret.

I do not venture out nights the Mosquito Abatement District is spraying my neighborhood. My windows and doors are shut. How do I know when they’ve paid a visit? When the fireflies stop.