The Schmidt sting pain index is a pain scale rating the relative pain caused by different hymenopteran stings. It is mainly the work of Justin O. Schmidt (born 1947), an entomologist at the Carl Hayden Bee Research Center in Arizona. Schmidt has published a number of papers on the subject, and claims to have been stung by the majority of stinging Hymenoptera.
His original paper in 1983 was an attempt to systematize and compare the hemolytic properties of insect venoms. The index contained in the paper started from 0 for stings that are completely ineffective against humans, progressed through 2, a familiar pain such as a common bee or wasp sting and finished at 4 for the most painful stings. In the conclusion, some descriptions of the most painful examples were given, e.g.: "Paraponera clavata stings induced immediate, excruciating pain and numbness to pencil-point pressure, as well as trembling in the form of a totally uncontrollable urge to shake the affected part."
Subsequently, Schmidt has refined his scale, culminating in a paper published in 1990, which classifies the stings of 78 species and 41 genera of Hymenoptera. Schmidt described some of the experiences in vivid detail.
An entry in The Straight Dope reported that "implausibly exact numbers" which do not appear in any of Schmidt’s published scientific papers were "wheedled out of him" by Outside magazine for an article it published in 1996.
The 10 most painful stings on the planet, by the self-sacrificing man who tried 150 different varieties in the name of science
Schmidt Pain Scale with Photos of insects