Meganeura, meaning "Large-Nerved," is a prehistoric griffinfly named after the veins in its giant wings. Griffinflies are similar to dragon- flies, but lack a feature of  dragonfly wings. Meganeura was one of the largest griffinflies, with a wingspan of 70 centimeters! There are several hypotheses about why  these insects got to be so huge, but none are completely sufficient explanations. The most popular  states that higher oxygen levels  allowed them to grow larger, and   while there is some evidence to   support this, the fact that species  of giant flying insects exist in  later, less oxygenated time periods casts some doubt on this explanation.  Another hypothesis refers to a lack  of predators to eat them, letting  them grow to maximum size and eat  larger prey.  Meganeura lived in the Late Carbon- iferous Period alongside its fellow giant arthropod Arthropleura in an environment called the coal forest. The coal forest was a rainforest- like wetland that later became the coal we burn today (hence the name). These forests supported a diverse ecosystem that ranged from inverte- brates like Meganeura to ancient amphibians and reptiles. Meganeura thrived in this environment,  feasting on other insects like the flying herbivores of the order Palaeodictyoptera.