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We studied the life cycle of H. tropicus in a tropical locality in the state of Chiapas, Mexico. Monthly, a minimum of 15 nests were collected, recording the exact contents of each nest throughout the year (1982-1983). In this place, in which the climate corresponds to the driest of the hot-humid climates, H. tropicus is the more common species of Passalids among the other 4 present in this locality. It seems to be very unspecific in it's choice of tree species in which to nest; the state of decomposition (intermediate) and humidity (60-80%), appear to be the factors which affect the selection of the wood to be used. The tunnel is started by a single individual, usually the female (71.4%, n = 28) which later pairs with the opposite sex. Reproduction, as noted from presence of eggs, occurs during the second half of the year after the start of the rainy season; pupation, in contrast to reproduction, occurs during the dry season. Larvae can be found during practically the whole year, but the appearance of the various stages occurs progressively. The factor that seems to determine this periodicity is the existence of a fairly prolonged dry season in this locality which limits reproduction to some months of the year. The results obtained demonstrate that a female can achieve various discontinuous ovipositions during the reproductive period. This characteristic, together with the fact that in young adults remain in the maternal nest for several months, may play an important role in the social structure of these insects. Due to the combination of both phenomena, individuals of a range of ages coexist in the same gallery. We also conclude, by observing the cuticular pigmentation, that reproductive individuals originate from the most recent generation (adults less than a year old). Apparently this species only reproduces during its first year under the environmental conditions in this locality. Inglés