Oribatid mites lack photoreceptors; yct adults of Scheloribates parabilis showed an increasing negative phototactic response to U.V., white, and green light with increased intensity; a decreasing negative phototactic response to blue light with increased intensity; and an increasing positive phototactic response to increasing intensity of purple light. Light and heat relationships are discussed. Correlation is made with the presence of salivary glands in adult oribatids and phototactic responses. Immature stages lack salivary glands and show no response to light.