The insects are about four times larger than the common honey bee or about as long as a human thumb. A solitary female bee was finally seen in the Indonesian province of North Maluku on the Maluku Islands, after researchers investigated the region for five days.
You might think the world's biggest bee would be easy to find.
Those in the environmental community have reason to celebrate this week, as not one, but two otherwise missing species have been rediscovered by researchers and conservation groups on the Galapagos Islands and in Indonesia.
This undated handout picture provided by Global Wildlife Conservation February 21, 2019, shows entomologist and bee expert Eli Wyman with the first rediscovered individual of Wallace's giant bee (Megachile pluto) in the Indonesian islands of the North Moluccas.
Little is known about these elusive insects' habits.
Wallace's Giant Bee (named after Alfred Russel Wallace, who found the bee in 1958), was last seen in 1981.
Eli Wyman with one of the only known Wallace’s giant bee samples
Tapia's expedition team also reportedly found additional tracks and scents that may belong to other members of the species, meaning this grand old lady might not be alone.
"It was absolutely breathtaking to see this "flying bulldog" of an insect that we weren't sure existed anymore, to have real proof right there in front of us in the wild", said Clay Bolt, the photographer who captured the first image of the insect.
He said female bees appear to be "very docile", and that unlike social honeybees, they do not tend to sting.
"All that we know at the moment is that it makes nests inside termite mounds, it has incredibly large mandibles which collects resin from trees and it lines the nest with that resin which probably acts as an antifungal device ... there is a lot to be learnt about that antiseptic" he said.
Currently, there is no legal protection addressing trade in the endangered Wallace's giant bee.
The giant bee's build "communal nests on termite dwellings", according to CBS news. "Number one, to see it in the wild, to document it, but also to make local contacts in Indonesia that could begin to work with us as partners to try and figure out how to protect the bee".
Professor Robson was with a team organised by Global Wildlife Conservation, a Texas-based organisation that runs a Search for Lost Species program, when the bee was discovered. And if it needs help, how can we best preserve what remains of the world's largest bee species?
Female specimens of the bee can reach a length of 3.8 centimetres and have a wingspan of more than six centimetres.