The Morphing Micro Air and Land Vehicle (MMALV) is based on "passive mechanics" of cockroach and bat locomotion.
Three prototypes were built based on studies of the mechanics of thin, undercambered, bat-like wings and abstracted cockroach ground locomotion mechanisms.
One MLV is capable of flying and walking, and successfully transitions between locomotion modalities. An insect-like wing retraction mechanism has also been designed.
Read more here