The MED1O2 allele is a C to T mutation at mRNA position 1373 (genomic position:  3L:21633009 ), and thus corresponds to a CAA (Glutamine codon, at position 408 within the three alternative MED1 ORFs) to TAA (Stop codon) open-reading frame alteration, resulting in a 407 aa long truncated protein. This is a correction of the location reported in the publication (FBrf0241861).
As far as I know, the deleted sequences from the MED1Δ9 and MED1Δ98 alleles have not been precisely determined, being only inferred from Southern blot analyses.