Limited overs cricket is always scheduled for completion in a single day. There are two types: List A which normally allows fifty overs per team; and Twenty20 in which the teams have twenty overs each. Both of the limited overs forms are played internationally as Limited Overs Internationals (LOI) and Twenty20 Internationals (T20I). List A was introduced in England in the 1963 season as a knockout cup contested by the first-class county clubs. In 1969, a national league competition was established. The concept was gradually introduced to the other leading cricket countries and the first limited overs international was played in 1971. In 1975, the first Cricket World Cup took place in England. Twenty20 is a new variant of limited overs itself with the purpose being to complete the match within about three hours, usually in an evening session. The first Twenty20 World Championship was held in 2007. Limited overs matches cannot be drawn, although a tie is possible and an unfinished match is a "no result".
The phylogenetic relationships of the Gryllidae, summarized by Darryl Gwynne in 1995 from his own work (using mainly anatomical characteristics) and that of earlier authors,[a] are shown in the following cladogram, with the Orthoptera divided into two main groups, Ensifera (crickets sensu lato) and Caelifera (grasshoppers). Fossil Ensifera are found from the late Carboniferous period (300 Mya) onwards, and the true crickets, Gryllidae, from the Triassic period (250 to 200 Mya).
The match details, including runs and dismissals, are recorded by two official scorers, one representing each team. The scorers are directed by the hand signals of an umpire (see image, right). For example, the umpire raises a forefinger to signal that the batsman is out (has been dismissed); he raises both arms above his head if the batsman has hit the ball for six runs. The scorers are required by the Laws to record all runs scored, wickets taken and overs bowled; in practice, they also note significant amounts of additional data relating to the game.
In cricket, the rules of the game are specified in a code called The Laws of Cricket (hereinafter called "the Laws") which has a global remit. There are 42 Laws (always written with a capital "L"). The earliest known version of the code was drafted in 1744 and, since 1788, it has been owned and maintained by its custodian, the Marylebone Cricket Club (MCC) in London.
Crickets have from time to time appeared in poetry. William Wordsworth's 1805 poem The Cottager to Her Infant includes the couplet "The kitten sleeps upon the hearth, The crickets long have ceased their mirth". John Keats's 1819 poem Ode to Autumn includes the lines "Hedge-crickets sing; and now with treble soft / The redbreast whistles from a garden-croft". The Chinese Tang dynasty poet Du Fu (712–770) wrote a poem that in the translation by J. P. Seaton begins "House cricket ... Trifling thing. And yet how his mournful song moves us. Out in the grass his cry was a tremble, But now, he trills beneath our bed, to share his sorrow."