Eye colour: dark red. Recessive auxotroph for guanosine; supplementable by 3.2 mM of guanosine but not by other ribonucleosides or nucleic acid bases. Inosine dehydrogenase activity of burgua larval extracts an order of magnitude lower than that of wild type.
Allelism of bur2 inferred from map position of 2-54 and phenotype.