Using deletion mapping and complementation tests, we have localized 5 behavioral mutations: shaking-B2, small optic lobesKS58, sluggish-AEE85, stonedts1, and stress-sensitive-C1 to 4 genetic complementation groups at the base of the X-chromosome. Shaking-B2 is an allele of the lethal complementation group R-9-29 near band 19E3; small optic lobesKS58 and sluggish-AEE85 belong to adjacent complementation groups, between lethals W2 and A112 near band 19F4; and stonedts1 and stress-sensitive-C1 are both alleles of the 8P1 lethal complementation group between lethals 114 and 13E3 near bands 20B-C.