42 ENTOMOLOGICAL NEWS NOTE ON COLLEMBOLA OF PEDREGAL DE SAN ANGEL, MEXICO, D.F. 1 Jose G. Palacios-Vargas ABSTRACT: Seventeen taxa of Collembola, representing fourteen genera, are cited for the first time from the Pedregal de San Angel. Thirteen of these species are new for Mexico, D.F. and twelve are recorded as new for the country. RESUMEN: 17 taxade Collembola, representando 14ge'neros,son citados por vezprimera del Pedregal de San Angel. 13 de estas especies son nuevas para Mexico, D.F. y 12 son registradas como nuevas para el pais. Pedregal de San Angel is located in the Southwest region of the narrow Valley of Mexico and is part of the Xochimilco and Chalco region. (Between 1 9 14' and 1 9 25' North latitude and 9908' and 99 1 5' West). The soil is mainly basaltic rock with an age of about 2500 years. The altitude in the northern part, where most of the samples were taken, is between 2250 and 2400 m. The climate (Garcia, 1964) is Cw 2 (w) b (f), and is the most humid of the temperate subhumid climates, with its rainy season during the summer but less than 5% of the annual precipitation during the winter. The summer is long and fresh with a monthly temperature average between 11.9 C in January and 17.5C in June; rainfall ranges from 3.4 mm during February to 221 .2 mm in July. The vegetation is a Fniticetum (Rzedowsky, 1954) with the dominant species, Senecio praecox (Com-positae), flowering in September and October. Some interesting papers have been written about the Pedregal de San Angel, such as that of Rzedowski ( op. cit. ) and Diego ( 1 970) concerning the vegetation, and the works of Bravo (1975), Carbajal (1975), Lechuga ( 1 97 1 ) and Serrano ( 1 970), dealing with insects. There is one paper about the spiders (Ibarra, 1979) but none about the springtails. Some articles concerning the Collembola from Distrito Federal, Mexico, have been written (Bonet, 1942, 1944, 1945, 1947, Folsom, 1898; Handschin, 1928; Yosii, 1962) in which a total of 34 species have been cited. These are mainly from forests. Nothing has been said about those species occurring in the lava flows or on rocky ground. During the past five years, some samples of litter and soil have been taken, along the basaltic zone, close to the university campus. The Collembola were identified by the author and determinations were checked Deceived June 23, 1980. Laboratorio de Acarologia, Departamento de Biologia, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Mexico 20, D.F. ENT. NEWS 92(1): 42-44
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