Gryllus firmus exhibits wing polymorphism; some individuals have fully functional, long hind wings and others have short wings and cannot fly. The short-winged females have smaller flight muscles, greater ovarian development, and produce more eggs, so the polymorphism adapts the cricket for either dispersal or reproduction. In some long-winged individuals, the flight muscles deteriorate during adulthood and the insect's reproductive capabilities improve.[13]
A bowler reaches his delivery stride by means of a "run-up" and an over is deemed to have begun when the bowler starts his run-up for the first delivery of that over, the ball then being "in play".[82] Fast bowlers, needing momentum, take a lengthy run up while bowlers with a slow delivery take no more than a couple of steps before bowling. The fastest bowlers can deliver the ball at a speed of over 145 kilometres per hour (90 mph) and they sometimes rely on sheer speed to try to defeat the batsman, who is forced to react very quickly.[90] Other fast bowlers rely on a mixture of speed and guile by making the ball seam or swing (i.e. curve) in flight. This type of delivery can deceive a batsman into miscuing his shot, for example, so that the ball just touches the edge of the bat and can then be "caught behind" by the wicket-keeper or a slip fielder.[90] At the other end of the bowling scale is the spin bowler who bowls at a relatively slow pace and relies entirely on guile to deceive the batsman. A spinner will often "buy his wicket" by "tossing one up" (in a slower, steeper parabolic path) to lure the batsman into making a poor shot. The batsman has to be very wary of such deliveries as they are often "flighted" or spun so that the ball will not behave quite as he expects and he could be "trapped" into getting himself out.[91] In between the pacemen and the spinners are the medium paced seamers who rely on persistent accuracy to try to contain the rate of scoring and wear down the batsman's concentration.[90]
The main objective of each team is to score more runs than their opponents but, in some forms of cricket, it is also necessary to dismiss all of the opposition batsmen in their final innings in order to win the match, which would otherwise be drawn.[66] If the team batting last is all out having scored fewer runs than their opponents, they are said to have "lost by n runs" (where n is the difference between the aggregate number of runs scored by the teams). If the team that bats last scores enough runs to win, it is said to have "won by n wickets", where n is the number of wickets left to fall. For example, a team that passes its opponents' total having lost six wickets (i.e., six of their batsmen have been dismissed) have won the match "by four wickets".[66]
Cricket has close historical ties with Australian rules football and many players have competed at top levels in both sports.[136] In 1858, prominent Australian cricketer Tom Wills called for the formation of a "foot-ball club" with "a code of laws" to keep cricketers fit during the off-season. The Melbourne Football Club was founded the following year, and Wills and three other members codified the first laws of the game.[137] It is typically played on modified cricket fields.[138]
Crickets have many natural enemies and are subject to various pathogens and parasites. They are eaten by large numbers of vertebrate and invertebrate predators and their hard parts are often found during the examination of animal intestines.[4] Mediterranean house geckos (Hemidactylus turcicus) have learned that although a calling decorated cricket (Gryllodes supplicans) may be safely positioned in an out-of-reach burrow, female crickets attracted to the call can be intercepted and eaten.[17]
Crickets are hemimetabolic insects, whose lifecycle consists of an egg stage, a larval or nymph stage that increasingly resembles the adult form as the nymph grows, and an adult stage. The egg hatches into a nymph about the size of a fruit fly. This passes through about 10 larval stages, and with each successive moult, it becomes more like an adult. After the final moult, the genitalia and wings are fully developed, but a period of maturation is needed before the cricket is ready to breed.[20] 

While the umpire (1) in shot stands at the bowler's end of the pitch, his colleague stands in the outfield, usually in or near the fielding position called "square leg", so that he is in line with the popping crease (7) at the striker's end of the pitch. The bowling crease (not numbered) is the one on which the wicket is located between the return creases (12). The bowler (4) intends to hit the wicket (9) with the ball (5) or, at least, to prevent the striker (8) from scoring runs. The striker (8) intends, by using his bat, to defend his wicket and, if possible, to hit the ball away from the pitch in order to score runs.
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,[31][32] and the true crickets, Gryllidae, from the Triassic period (250 to 200 Mya).[1]
Some species, such as the ground crickets (Nemobiinae), are wingless; others have small fore wings and no hind wings (Copholandrevus), others lack hind wings and have shortened fore wings in females only, while others are macropterous, with the hind wings longer than the fore wings. In Teleogryllus, the proportion of macropterous individuals varies from very low to 100%. Probably, most species with hind wings longer than fore wings engage in flight.[3]

The most famous player of the 19th century was W. G. Grace, who started his long and influential career in 1865. It was especially during the career of Grace that the distinction between amateurs and professionals became blurred by the existence of players like him who were nominally amateur but, in terms of their financial gain, de facto professional. Grace himself was said to have been paid more money for playing cricket than any professional.[citation needed]

Male crickets establish their dominance over each other by aggression. They start by lashing each other with their antennae and flaring their mandibles. Unless one retreats at this stage, they resort to grappling, at the same time each emitting calls that are quite unlike those uttered in other circumstances. When one achieves dominance, it sings loudly, while the loser remains silent.[17]
Crickets are small to medium-sized insects with mostly cylindrical, somewhat vertically flattened bodies. The head is spherical with long slender antennae arising from cone-shaped scapes (first segments) and just behind these are two large compound eyes. On the forehead are three ocelli (simple eyes). The pronotum (first thoracic segment) is trapezoidal in shape, robust, and well-sclerotinized. It is smooth and has neither dorsal or lateral keels (ridges).[3]
The ICC also organises competitions that are for several countries at once, including the Cricket World Cup, ICC T20 World Cup and ICC Champions Trophy. A league competition for Test matches played as part of normal tours, the ICC World Test Championship, had been proposed several times, and its first instance began in 2019. A league competition for ODIs, the 2020–22 ICC Cricket World Cup Super League, is planned to begin in 2020. The ICC maintains Test rankings, ODI rankings and T20 rankings systems for the countries which play these forms of cricket.
At the grassroots level, local club cricket is essentially an amateur pastime for those involved but still usually involves teams playing in competitions at weekends or in the evening. Schools cricket, first known in southern England in the 17th century, has a similar scenario and both are widely played in the countries where cricket is popular.[125] Although there can be variations in game format, compared with professional cricket, the Laws are always observed and club/school matches are therefore formal and competitive events.[126] The sport has numerous informal variants such as French cricket.[127]