The results of a study on the fauna of Cerambycidae of the tropical dry forest of "El Aguacero," Chiapas, Mexico are presented. Data were obtained during a year of monthly collections and records obtained during sporadic collections carried out mainly during the rainy season. A total of 203 species, representing 119 genera, 42 tribes and four subfamilies were recorded. Seventy-nine species were recorded for the first time for the state of Chiapas. The subfamilies with the greater numbers of

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... ies, genera and tribes were the Cerambycinae with 111, 66 and 22 and Lamiinae with 81, 45 and 16, respectively. The genera with the greatest numbers of species were Stenosphenus Haldeman, Sphaenothecus Dupont, Lepturges Bates and Phaea Newman with six each and Anelaphus Linsley, Psyrassa Pascoe, Neocompsa Martins and Acyphoderes Serville with five each. The largest number of species was recorded during June (101) and the least during March (two); the largest number of individuals was recorded during September and the least during February. Seasonally, 165 species were collected during the rainy season, 17 during the dry season and 21 during both. Six hundred twenty two individuals were collected during the rainy season and 249 during the dry season. The species abundance pattern showed few abundant species and many with few individuals (63% were represented by three or fewer individuals). The most abundant species were Stenosphenus cribripennis cribripennis Thomson (51 individuals), Essostrutha laeta (Newman) (45), Ironeus pulcher Bates (43), Ochraethes sp. near O. sommeri (Chevrolat) (38), Sphaenothecus toledoi Chemsak and Noguera (33), Sphaenothecus trilineatus Dupont (31), Ochraethes pollinosa Chevrolat (31) and Sphaenothecus maccartyi Chemsak and Noguera (30). The seasonal activity of most species as adults was restricted, with 141 species found only during one month and 37 during two months. The fauna of "El Aguacero" was compared with two other similar sites in Mexico,