Measurements of insect length normally exclude legs, jaws, or horns, but if jaws are included, the longest known specimen of M. cervicornis is 17.7 cm; the longest known specimen of Dynastes hercules, a beetle species with enormous horns, is 17.5 cm, and the longest known beetle excluding either jaws or horns is Titanus giganteus, at 16.7 cm.
When measuring insects, lengths usually do not include legs, jaws, or horns; however, if jaws are included, the largest specimen of M. cervicornis measures 17.7 cm; the longest known specimen of Dynastes hercules, a beetle with large horns, is 17.5 cm; and the longest insect without legs, jaws, or horns is Titanus giganteus at 16.7 cm.