Sickle-flies
An enormous breed of insect native to the Midgewater Marshes of Bree-land, the sickle-flies and their brood have since begun to spread to other lands of Middle-earth. Whether this is through natural migration or if they are driven by some dark intelligence is unclear. Like the giant Spiders, the sickle-flies seem to be gaining in size and aggression, seeking out new lands in which to multiply and find prey.
The enormous Glowing Fire-fly (Evendim) and Glowing Fire-fly (Eregion) seem to be related to the sickle-flies, or at least have similar attributes.
Additionally, giant hornets such as those found in the Southern Old Forest also share similarities.
Sickle-flies are found in marshy areas and fields. They are "normal" difficulty and are mostly aggressive,though some threaten to attack. They are weak to Beleriand damage.
Background
Sickle-flies do not appear in the work of J.R.R. Tolkien. They were created for The Lord of the Rings Online. As with Tolkien's giant spiders, the game presumes that many insects and arachnids of Middle-earth are of enormous size.
An index of all known sightings: