The polyembryonic wasp, Copidosoma floridanum parasitizes the egg of its host caterpillar, Trichoplusia ni. C. floridanum produces up to 3000 genetically identical embryos. A unique attribute of polyembryonic wasps is the host’s tracheae grow directly towards the embryos supplying oxygen to the developing embryos. A key regulator of tracheal growth is the signaling factor Branchless. We characterized a branchless homolog in C. floridanum describing the sequence and discussing the potential role the gene plays.