The Heteroptera are a group of about 40,000 species of insects in the order Hemiptera. Sometimes called "true bugs", that name more commonly refers to the Hemiptera as a whole, and "typical bugs" might be used as a more unequivocal alternative since among the Hemiptera, the heteropterans are most consistently and universally termed "bugs". "Heteroptera" is Greek for "different wings": most species have forewings with both membranous and hardened portions (called hemelytra); members of the primitive Enicocephalomorpha have completely membranous wings.