EVOLUTION. For the article “Distinct roles of the homeotic genes Ubx and abd-A in beetle embryonic abdominal appendage development” by David L. Lewis, Mark DeCamillis, and Randy L. Bennett, which appeared in number 9, April 25, 2000, of Proc. Natl. Acad. Sci. USA (97, 4504–4509), the authors note the following correction. In Materials and Methods, we failed to cite the source of the Utx^m115 mutant. Utx^m115 was isolated in the laboratory of Dr. Robin Denell by Dr. Susan Brown and colleagues in a screen for recessive lethals within the homeotic complex of Tribolium [see Proc. Natl. Acad. Sci. USA (97, 4510–4514)]. We are grateful to Rob Denell and Sue Brown for providing the Utx^m115 strain and for communicating unpublished results.