It's a tale as old as time: Scientist collects a ton of bug specimens, they get packed away on a shelf, and decades later someone else discovers the "new" species that have been collecting dust all along.

In a new paper in ZooKeys, Bruno Massa of the University of Palermo describes four such new species. He found them all in just one month of studying the untapped insect collections of museums in Madrid and Berlin.

"European museums preserved collections containing thousands of specimens coming from all the world in the last two centuries," Massa said. "Of course, many of them still need to be studied and identified."

Because the scientists who are experts in classifying species are often quite specialized, not every captured bug or fossilized specimen can be interpreted closely by just anyone. It's not enough to be an insect expert -- to really distinguish these collected crickets from previously known species, one must be a cricket expert.

"When you are collecting alive specimens, you may obtain further information on them, such as emitted songs in the case of grasshoppers and crickets," Massa said. But when faced with a long-dead cricket in the bowels of a museum, close inspection of physical characteristics is all a researcher has to go on.

So even when museum collections aren't literally forgotten (as was the case with another cricket discovered last year after sitting under a sink for 50 years) it can take ages for new species to see the light of day.

Massa's favorite discovery -- a cricket with unusually long legs collected in Tanzania back in 1910 -- was actually pegged as a member of an unknown genus by a researcher who looked at it over 30 years ago. But he didn't have enough information to formally distinguish it from known crickets.

In honor of its long wait for classification, that little bug has been named Arostratum oblitum (from the Latin for "forgotten"). Even though it's been over a century, Massa said, it's likely that other members of the species are still hopping around.

Central Africa (where all of the new-old species were found) is especially rich with species of bush crickets. So as scientists like Massa continue to plow through old museum collections from the area, it's likely that even more forgotten treasures will be uncovered.

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