Metcalfa pruinosa (Say) (Hemiptera: Flatidae), the citrus flatid planthopper(CFP) is suddenly discovered this year in Seoul and Gyeonggi Province, Korea. CFP is originally distributed in the Eastern parts of North America(Metcalf and Bruner 1948), and recently spreading to European countries(Baker et al. 2008) such as northern Italy, Spain, and France. It is an economically important plant-sucking insect having wide host range including many agricultural crops such as grapefruit and citrus, and ornamental trees, camellias, azaleas, and magnolias(Dean and Bailey 1961) mediating plant viruses. We discovered large samples on Hosta longipes (Franch. & Sav.) Matsumura, Liriope platyphylla F.T.Wang & T.Tang, Weigela subsessilis L.H.Bailey, etc. in Seoul and Suwon on August 2009. In this report, we announce their taxonomic position, morphological characters, distribution, host information, and importance as a possible pest in the Korean peninsula.

• Yeyeun Kim(Insect Biosystematics Laboratory, Research Institute for Agricultural and Life Sciences, Department of Agricultural Biotechnology, Seoul National University)
• Sora Kim(Insect Biosystematics Laboratory, Research Institute for Agricultural and Life Sciences, Department of Agricultural Biotechnology, Seoul National University)
• Seunghwan Lee(Insect Biosystematics Laboratory, Research Institute for Agricultural and Life Sciences, Department of Agricultural Biotechnology, Seoul National University)