Abstract : This is one of three reports on the study of micro-robots. This document describes the design and construction of a series of small robotic vehicles. The designs incorporate biological inspiration from the cricket. The goal is a micro autonomous legged robot capable of traveling over a variety of terrains. The development of many components needed to build the robot, such as micro-McKibben artificial muscles, micro compressors, and MEMS (micro-electro-mechanical systems) - fabricated valves is also discussed. These components were first used in the design and construction of several prototype sub-systems such as a prototype leg and a simple non-autonomous hybrid vehicle that tests individual components before use in the fully integrated vehicles. From these prototypes two versions of an autonomous vehicle that use a combination of legs and wheels to locomote were developed. Two wheels support the front of the vehicles and two rear legs propel them. The valves distribute air, supplied by the compressor, from the plenum to the actuators on the rear legs. A six-legged non-autonomous vehicle was designed, constructed and tested. It was demonstrated to walk in a tripod gait. A second report (NATICK/TR-05/011) focuses on the investigation of a micro-joint angle sensor using MEMS Cilia, and a third report (NATICK/TR-05/012) examines micro-robots on abstracted biological principles.