The South Otago branch of Forest and Bird's junior arm - the Kiwi Conservation Club (KCC) - ran the event at insect theme park Earthlore, near Owaka, as part of the Catlins summer programme.
zAmong the miniature creatures unearthed were several moths and butterflies, centipedes, worms, a somewhat menacing nursery web spider, and a mother slater and her brood, the latter found by 10-year-old Brooklyn Smith, of Balclutha.
Brooklyn said she loved all animals, but was particularly fascinated by creepy-crawlies.
"My favourite bug today has been the baby slaters with their mum.
"We only took her away to look at for a little bit because it was important to get her back to her babies."
Taking a break from peering under rocks, Brooklyn's father Stan said he was also enjoying his visit.
"It's something different to do.
"It's good to have a country break from the usual beaches, swimming and television for a change."
KCC co-ordinator Catriona Gower said events like the family day inspired young people to grow to love the natural world.
"When you become fascinated by and grow to love nature as a child, you carry that affection and sense of care into adulthood.
"It's just lovely to see everyone's smiles, laughter and excitement today."
The Catlins was a "wonderland" for nature lovers of any age, she said.
"Earthlore have created a magic place here, expanding biodiversity and spreading the word.
"Some of our out-of-town visitors have just been stunned by the abundance and variety of wildlife on show."