When it is necessary to use a Latin name, follow the standard practice. Thus for all creatures higher than viruses, write the binomial name in italics, giving an initial capital to the first word (the genus): Turdus turdus, the song thrush; Metasequoia glyptostroboides, the dawn redwood; Culicoides clintoni, a species of midge. This rule also applies to Homo sapiens and to such cod uses as Homo economicus. On second mention, abbreviate the genus (T. turdus). In some species, such as dinosaurs, the genus alone is used in lieu of a common name: Diplodocus, Tyrannosaurus. Also Drosophila, a fruitfly favoured by geneticists. But Escherichia coli, a bacterium also favoured by geneticists, is known universally as E. coli, even on first mention.