Abstract
Eighteen genera of spider mites were collected by the authors during July and August in 1970. Two of these are proposed and described as new, Crotonella and Atetranychus. A total of sixty-nine species are reported, including thirteen new species. Descriptions and figures of new species are as follows: Mcgregorella lantanae, Paraplonobia (Langella) mexicana, Petrobia (Petrobia) waltheria, Crotonella mazatlana, Mononycheilus wainsteini, M. waltheria, M. tephrosiae, M. hyptis, Eoteranychus abutilon, E. brickiella, Atetranychus estebaneae, Oligonycnus, (Homonychus) constegia, and Tetranychus (Tetranychus) flechtmanni.
