The wasps are the size of a large ant, and they neither look nor behave like the wasps we're accustomed to.
"They don't do anything to humans. They don't attack. They don't bite. They're not stinging wasps," said Lake County Forest Preserve Crew Chief Mark Speckan.
The wasps are a natural predator of the emerald ash borer, an invasive beetle that has killed tens of millions of ash trees in Illinois and 12 other states.
"The borer... makes a zig-zag pattern," said Speckan. "Once they start cutting up [the] vascular system, the tree basically strangles."
In Lake County, the beetle infestation is still in its early stages.
"The bio control right now represents our best hope at controlling [the emerald ash borer]," said Lake County Forest Preserve ecologist Matt Ueltzen.
That is why forest preserve officials Speckan and Ueltzen were in the woods Thursday morning. After a few minutes of coaxing, hundreds of the insects were released into the wild.
"Now it's up to them," said Ueltzen.
Like the emerald ash borer, these predator wasps are native to Asia, and that does not sit well with some.
Forest Preserve commissioner Michelle Feldman voted against the wasp release, and in a statement, she said: "I am concerned about unintended consequences of introducing something into the environment which is so different than the original natural environment."
Speckan and Ueltzen say the federal government stands by the wasps.
"The USDA has done extensive trials for this bio control for these releases," said Ueltzen. "These wasps essentially consume [emerald ash borer] larvae only."
The insect release program is being funded by the federal government. Cook County has had a similar program for the past couple years, but those officials say it is too early to gauge whether or not the program is working.
The wasps likely will not eradicate the beetle, but officials hope it will slow the beetle's spread.
