hydrocyanic acid. that's what it's calledi have a swollen eye from itching and a brown stain on my hand.
not saying you're wrong, but i'd like to see it referenced from somewhere other than wikipediaactually i foudn out the american species does not spray acid but instead squirt
a noxious liquid that contains large amounts of benzoquinones
http://en.wikipedia.org/wiki/Narceus_americanus
"There have also been claims that rather than releasing benzoquinone, this North American millipede releases hydrogen cyanide; however, this is simply not true"