"Recent estimates put the total number of insect species known to science between 1 million and 2 million.  Whatever number we pick, we must remember that it is an estimate of the total number of names, not species.  Some species may have been described more than once; others may encompass several species that await formal description.."—from Arthur V. Evans and Charles L. Bellamy in An Inordinate Fondness for Beetles, Henry Holt and Company, Inc.,1996, p.20