Centipede

A centipede (ムカデ, Mukade) is a type of bug found, like pill bugs, under rocks by striking it with a shovel or an axe. They can be found in the months of June to February from 4pm to 11pm. They are worth 300 Bells.

In City Folk
Upon donation to the Museum, Blathers will say this about the centipede:

"Indeed, centipedes are quite fast to boot, wot? If the beast attacks us, how will we flee to safety? Moreover, they have hard shells, so we can't stop it with a furious stomping... We're doomed!"

Centipedes can be found on the second level, near the rafflesia, along with the fly and flea.

In New Leaf
Upon being donated, the centipede can be found in the upper left room of the bug exhibit, near the rafflesia. The exhibit has this to say about the Centipede:

"Despite the name, centipedes have a varying number of legs, from about 30 to 46 rather than 100. They also have forcipules, which are the modification of the first pair of legs, that inject venom. Centipedes are sometimes used as ingredient in herbal medicine, though the effect is questionable."

Further Information
The centipede in this game appears to be the brown centipede, found in Europe. Unlike what most people think, centipedes are not insects. They actually belong to the class of animals known as Chilopoda, which are close relatives to millipedes and small myriapods known as symphylids.

Trivia

 * In the Prima City Folk Guide, the bug guide states centipedes are found on flowers instead of rocks. This may have caused confusion to some players looking for the centipede.