An extensive field survey of Odonala of Illinois in 1984-1986 resulted in a number of new state records (including some range extensions), and a re-discovery of some species that have not been collected since 1933-1958. In addition to the species collected by the authors, others noted below were discovered in existing collections in the state. According to recent literature (J.G. NEEDHAM & M.J. WESTFALL, 1955, A manual of the dragonflies of North America, Univ. Calif. Press, Berkeley; B.E. MONTGOMERY, 1967, Proc. N. cent. Brcheni. Soc. Am. 22: 121-129; T.E. VOGT&J.E. McPHERSON, 1985. Gl Lakes Emomol. 18: 7-13) the listed species were not known to occur in Illinois. Except where noted, all specimens are in the Illinois State Museum Entomology Collection. Argia plana Calvert — Hancock Co.: Alice L. Life Science Station, 13-V1-1985, small spring-fed stream with limestone substrate, I I $, EDC, HDB, WJW & THV; confluence of Crystal and Glen Creeks near Warsaw. I3-VI-1985, 3 $, 2 $, EDC, HDB, WJW & TEV; 29-V11I-1985, spring-fed streams with limestone substrate, 1 9. TEV. These records extend the range of this species to the north.