Anelytron (/ˈɛlɪtrɒn/; from Ancient Greek ἔλυτρον (élutron) 'sheath, cover';pl.:elytra,/ˈɛlɪtrə/)[1][2] is a modified, hardenedforewing ofbeetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the familySchizopteridae are extremely similar; in true bugs, the forewings are calledhemelytra (sometimes alternatively spelled as "hemielytra"), and in most species only the basal half is thickened while the apex is membranous, but when they are entirely thickened the condition is referred to as "coleopteroid".[3] An elytron is sometimes also referred to as ashard.[4]
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The elytra primarily serve as protective wing-cases for thehindwings underneath, which are used for flying. To fly, a beetle typically opens the elytra and then extends the hindwings, flying while still holding the elytra open, though many beetles in the familiesScarabaeidae andBuprestidae can fly with the elytra closed (e.g., mostCetoniinae;[5]).
In a number of groups, the elytra are reduced to various degrees, (e.g., the beetle familiesStaphylinidae andRipiphoridae), or secondarily lost altogether, as in variousElateroidea lineages with wingless females.
In some flightless groups, the elytra are present but fused together, and the hindwings are absent (e.g., someground beetles (Carabidae),scarab beetles, andweevils).