A poor farmer and his wife live on a stony, barren New England farm. They work hard to coax a bare living from their rocky land. The woman draws their water from a nearby brook; her husband once tried to dig a well on their property, but came up dry.
One day, on her way to the brook, the farmer's wife sees a large beetle stuck on its back. Having a kind heart, the woman turns the beetle back onto its feet, and watches it scamper away. The next day, the same thing happens; and when the woman rights the beetle with her finger, she is amazed to hear it thank her for her help. Despite her surprise, she engages the beetle in conversation; the insect inquires about her life and its hard conditions. Learning about her need to draw water from the brook, the beetle tells the woman to dig a well and put a pump in it. The bug assures her that the couple will get water from the well — or something more precious.
The wife tells her husband what has happened. In humility, he accepts that there is still magic in the world if a beetle can talk, and sets about digging the well. His first effort is another dry hole; but the beetle instructs the wife to install a pump anyway. Once they do, they find that the pump produces not water, but money: five-dollar gold coins come one by one from the pump.
The couple are so pleased that they do not try to conceal their new wealth. When they drop gold coins in the collection basket at church, their minister questions them. After hearing their story, the minister tells them that what they have is either fairy gold that will disappear in 24 hours, or else stolen coin, since all real gold belongs to somebody.
The simple couple are distressed as this idea. The wife questions the beetle, and the bug assures the woman that the minister is wrong on both counts: the wealth is neither stolen nor fairy gold. He explains that he is in fact the king of the beetles, and has commanded his subjects to gather all the gold pieces that have been lost by people over the years, and stock the well with them.
Satisfied, the two pump their well dry of gold, and go to town to spend some of their hoard. Swelled with pride and vanity, they flash and flourish their money. The town's ne'er-do-wells realize an opportunity; racing to the farmhouse, they ransack the place until they find the remaining gold.
The farmer and his wife return with a procession of hangers-on and idlers — but find their house trashed and their money gone. The crowd ridicules them and leaves; boys throw stones at their little house. Returning to the brook for water once more, the woman finds the king beetle; he reproves her for pride and vanity. If they had kept their wealth secret, they might have it still. As it is, they have only lost that which had been lost before them, and probably would "be lost many times more before the world comes to an end."
"The Wonderful Pump" is the single tale in the collection illustrated by Norman P. Hall.
Baum's characters meet other animal royalty besides the king of the beetles. There is the Queen of the Field Mice in The Wonderful Wizard of Oz, the King of the Fairy Beavers in John Dough and the Cherub, the queen hippo in "The Laughing Hippopotamus" and the title character in "The King of the Polar Bears," among others.
For the pump that produces coins one by one, compare the purse that does the same in "The Queen of Quok."