Technical Abstract: Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays by scientists at the USDA Agricultural Research Service, Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida. Wild-type and mutant strains of Anastrepha suspensa, Bactroceru dorsalis, B.cucurbitae, Ceratitis capitata, and Toxotrypana curvicauda all supported hobo excision or deletion both in the presence and absence of co-injected hobo transposase, indicating a permissive state for hobo mobilityand the existence of endogenous systems capable of mobilizing hobo. In several strains hobo helper reduced excision. Excision depended on hobo sequences in the indicator plasmid, though almost all excisions were imprecise and the mobilizing systems appear mechanistically different from hobo. hobe related sequences were identified in all species except T. curuicauda. Parsimony analysis yielded a subgroup including the B. cucurbitae and C. capitata sequences along with hobo and Herma, and a separate, more divergent subgroup including theA . suspasa and B. dorsalis sequences. All of the sequences exist as multiple genomic elements, and a deleted form of the B. cucurbitae element exists in B. dorsalis. The hoberelated sequences are probably members of the hAT transposon family with some evolving from distant ancestor elements, while others may have originated from more recent horizontal transfers.