Three new species of the newly recorded genus Monochorhynchus Muir, 1917 from China, with observations on the fine structure of the mouthparts (Hemiptera: Fulgoromorpha: Derbidae)

The planthopper genus Monochorhynchus Muir, 1917 is reviewed, newly recorded from China, and transferred to the subtribe Lyddina. Three new species from China, M. dehongensis sp. nov., M. obscurus sp. nov., and M. psammochroma sp. nov., are described and illustrated based on morphological characteristics. A checklist of the species of Monochorhynchus, including their geographic distribution, is provided, along with an identification key to the known species. The ultrastructure of the mouthparts of M. dehongensis is briefly investigated using the scanning electron microscope. The functions and taxonomic value of these structures are discussed.