A, Mean EAG responses from trans-heterozygotes with GT8, an allele of no-ocelli, show enhancement of the Sco olfactory phenotype (+/+, n=9; Sco/CyO, n=6; Sco/GT8, n=7; GT8/CyO, n=5) * decreased compared to wild type, # decreased compared to Sco/CyO (P < 0.008 in a Bonferroni-corrected t test). B, Mean EAG responses show that two revertant Sco alleles that affect the juxtaposition of sna and no-ocelli do not have the Sco olfactory phenotype (data for +/+ and Sco/CyO are same as A, Sco-rv11/CyO, n=6, Sco-rv25/CyO, n=6).