The smallest family members are the closely related short-tailed pygmy tyrant and black-capped pygmy tyrant from the genus "Myiornis" (the first species usually being considered marginally smaller on average). These species reach a total length of and a weight of 4–5 grams. By length, they are the smallest passerines on earth, although some species of Old World warblers apparently rival them in their minuscule mean body masses if not in total length. The minuscule size and very short tail of the "Myiornis" pygmy tyrants often lend them a resemblance to a tiny ball or insect. The largest tyrant flycatcher is the great shrike-tyrant at and . A few species such as the streamer-tailed tyrant, scissor-tailed flycatcher and fork-tailed flycatcher have a larger total length (up to ), but this is mainly due to their extremely long tails; the fork-tailed flycatcher has relatively the longest tail feathers of any known bird.